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diff --git a/ebtables-legacy.8.in b/ebtables-legacy.8.in new file mode 100644 index 0000000..3417045 --- /dev/null +++ b/ebtables-legacy.8.in @@ -0,0 +1,1146 @@ +.TH EBTABLES 8 "@PACKAGE_DATE@" +.\" +.\" Man page written by Bart De Schuymer <bdschuym@pandora.be> +.\" It is based on the iptables man page. +.\" +.\" The man page was edited, February 25th 2003, by +.\" Greg Morgan <" dr_kludge_at_users_sourceforge_net > +.\" +.\" Iptables page by Herve Eychenne March 2000. +.\" +.\" This program is free software; you can redistribute it and/or modify +.\" it under the terms of the GNU General Public License as published by +.\" the Free Software Foundation; either version 2 of the License, or +.\" (at your option) any later version. +.\" +.\" This program is distributed in the hope that it will be useful, +.\" but WITHOUT ANY WARRANTY; without even the implied warranty of +.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +.\" GNU General Public License for more details. +.\" +.\" You should have received a copy of the GNU General Public License +.\" along with this program; if not, write to the Free Software +.\" Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +.\" +.\" +.SH NAME +ebtables-legacy (@PACKAGE_VERSION@) \- Ethernet bridge frame table administration (legacy) +.SH SYNOPSIS +.BR "ebtables " [ -t " table ] " - [ ACDI "] chain rule specification [match extensions] [watcher extensions] target" +.br +.BR "ebtables " [ -t " table ] " -P " chain " ACCEPT " | " DROP " | " RETURN +.br +.BR "ebtables " [ -t " table ] " -F " [chain]" +.br +.BR "ebtables " [ -t " table ] " -Z " [chain]" +.br +.BR "ebtables " [ -t " table ] " -L " [" -Z "] [chain] [ [" --Ln "] | [" --Lx "] ] [" --Lc "] [" --Lmac2 ] +.br +.BR "ebtables " [ -t " table ] " -N " chain [" "-P ACCEPT " | " DROP " | " RETURN" ] +.br +.BR "ebtables " [ -t " table ] " -X " [chain]" +.br +.BR "ebtables " [ -t " table ] " -E " old-chain-name new-chain-name" +.br +.BR "ebtables " [ -t " table ] " --init-table +.br +.BR "ebtables " [ -t " table ] [" --atomic-file " file] " --atomic-commit +.br +.BR "ebtables " [ -t " table ] [" --atomic-file " file] " --atomic-init +.br +.BR "ebtables " [ -t " table ] [" --atomic-file " file] " --atomic-save +.br + +.SH LEGACY +This tool uses the old xtables/setsockopt framework, and is a legacy version +of ebtables. That means that a new, more modern tool exists with the same +functionality using the nf_tables framework and you are encouraged to migrate now. +The new binaries (known as ebtables-nft and formerly known as ebtables-compat) +uses the same syntax and semantics than this legacy one. + +You can still use this legacy tool. You should probably get some specific +information from your Linux distribution or vendor. +More docs are available at https://wiki.nftables.org + +.SH DESCRIPTION +.B ebtables +is an application program used to set up and maintain the +tables of rules (inside the Linux kernel) that inspect +Ethernet frames. +It is analogous to the +.B iptables +application, but less complicated, due to the fact that the Ethernet protocol +is much simpler than the IP protocol. +.SS CHAINS +There are three ebtables tables with built-in chains in the +Linux kernel. These tables are used to divide functionality into +different sets of rules. Each set of rules is called a chain. +Each chain is an ordered list of rules that can match Ethernet frames. If a +rule matches an Ethernet frame, then a processing specification tells +what to do with that matching frame. The processing specification is +called a 'target'. However, if the frame does not match the current +rule in the chain, then the next rule in the chain is examined and so forth. +The user can create new (user-defined) chains that can be used as the 'target' +of a rule. User-defined chains are very useful to get better performance +over the linear traversal of the rules and are also essential for structuring +the filtering rules into well-organized and maintainable sets of rules. +.SS TARGETS +A firewall rule specifies criteria for an Ethernet frame and a frame +processing specification called a target. When a frame matches a rule, +then the next action performed by the kernel is specified by the target. +The target can be one of these values: +.BR ACCEPT , +.BR DROP , +.BR CONTINUE , +.BR RETURN , +an 'extension' (see below) or a jump to a user-defined chain. +.PP +.B ACCEPT +means to let the frame through. +.B DROP +means the frame has to be dropped. In the +.BR BROUTING " chain however, the " ACCEPT " and " DROP " target have different" +meanings (see the info provided for the +.BR -t " option)." +.B CONTINUE +means the next rule has to be checked. This can be handy, f.e., to know how many +frames pass a certain point in the chain, to log those frames or to apply multiple +targets on a frame. +.B RETURN +means stop traversing this chain and resume at the next rule in the +previous (calling) chain. +For the extension targets please refer to the +.B "TARGET EXTENSIONS" +section of this man page. +.SS TABLES +As stated earlier, there are three ebtables tables in the Linux +kernel. The table names are +.BR filter ", " nat " and " broute . +Of these three tables, +the filter table is the default table that the command operates on. +If you are working with the filter table, then you can drop the '-t filter' +argument to the ebtables command. However, you will need to provide +the -t argument for the other two tables. Moreover, the -t argument must be the +first argument on the ebtables command line, if used. +.TP +.B "-t, --table" +.br +.B filter +is the default table and contains three built-in chains: +.B INPUT +(for frames destined for the bridge itself, on the level of the MAC destination address), +.B OUTPUT +(for locally-generated or (b)routed frames) and +.B FORWARD +(for frames being forwarded by the bridge). +.br +.br +.B nat +is mostly used to change the mac addresses and contains three built-in chains: +.B PREROUTING +(for altering frames as soon as they come in), +.B OUTPUT +(for altering locally generated or (b)routed frames before they are bridged) and +.B POSTROUTING +(for altering frames as they are about to go out). A small note on the naming +of chains PREROUTING and POSTROUTING: it would be more accurate to call them +PREFORWARDING and POSTFORWARDING, but for all those who come from the +iptables world to ebtables it is easier to have the same names. Note that you +can change the name +.BR "" ( -E ) +if you don't like the default. +.br +.br +.B broute +is used to make a brouter, it has one built-in chain: +.BR BROUTING . +The targets +.BR DROP " and " ACCEPT +have a special meaning in the broute table (these names are used instead of +more descriptive names to keep the implementation generic). +.B DROP +actually means the frame has to be routed, while +.B ACCEPT +means the frame has to be bridged. The +.B BROUTING +chain is traversed very early. However, it is only traversed by frames entering on +a bridge port that is in forwarding state. Normally those frames +would be bridged, but you can decide otherwise here. The +.B redirect +target is very handy here. +.SH EBTABLES COMMAND LINE ARGUMENTS +After the initial ebtables '-t table' command line argument, the remaining +arguments can be divided into several groups. These groups +are commands, miscellaneous commands, rule specifications, match extensions, +watcher extensions and target extensions. +.SS COMMANDS +The ebtables command arguments specify the actions to perform on the table +defined with the -t argument. If you do not use the -t argument to name +a table, the commands apply to the default filter table. +Only one command may be used on the command line at a time, except when +the commands +.BR -L " and " -Z +are combined, the commands +.BR -N " and " -P +are combined, or when +.B --atomic-file +is used. +.TP +.B "-A, --append" +Append a rule to the end of the selected chain. +.TP +.B "-D, --delete" +Delete the specified rule or rules from the selected chain. There are two ways to +use this command. The first is by specifying an interval of rule numbers +to delete (directly after +.BR -D ). +Syntax: \fIstart_nr\fP[\fI:end_nr\fP] (use +.B -L --Ln +to list the rules with their rule number). When \fIend_nr\fP is omitted, all rules starting +from \fIstart_nr\fP are deleted. Using negative numbers is allowed, for more +details about using negative numbers, see the +.B -I +command. The second usage is by +specifying the complete rule as it would have been specified when it was added. Only +the first encountered rule that is the same as this specified rule, in other +words the matching rule with the lowest (positive) rule number, is deleted. +.TP +.B "-C, --change-counters" +Change the counters of the specified rule or rules from the selected chain. There are two ways to +use this command. The first is by specifying an interval of rule numbers +to do the changes on (directly after +.BR -C ). +Syntax: \fIstart_nr\fP[\fI:end_nr\fP] (use +.B -L --Ln +to list the rules with their rule number). The details are the same as for the +.BR -D " command. The second usage is by" +specifying the complete rule as it would have been specified when it was added. Only +the counters of the first encountered rule that is the same as this specified rule, in other +words the matching rule with the lowest (positive) rule number, are changed. +In the first usage, the counters are specified directly after the interval specification, +in the second usage directly after +.BR -C . +First the packet counter is specified, then the byte counter. If the specified counters start +with a '+', the counter values are added to the respective current counter values. +If the specified counters start with a '-', the counter values are decreased from the respective +current counter values. No bounds checking is done. If the counters don't start with '+' or '-', +the current counters are changed to the specified counters. +.TP +.B "-I, --insert" +Insert the specified rule into the selected chain at the specified rule number. If the +rule number is not specified, the rule is added at the head of the chain. +If the current number of rules equals +.IR N , +then the specified number can be +between +.IR -N " and " N+1 . +For a positive number +.IR i , +it holds that +.IR i " and " i-N-1 +specify the same place in the chain where the rule should be inserted. The rule number +0 specifies the place past the last rule in the chain and using this number is therefore +equivalent to using the +.BR -A " command." +Rule numbers structly smaller than 0 can be useful when more than one rule needs to be inserted +in a chain. +.TP +.B "-P, --policy" +Set the policy for the chain to the given target. The policy can be +.BR ACCEPT ", " DROP " or " RETURN . +.TP +.B "-F, --flush" +Flush the selected chain. If no chain is selected, then every chain will be +flushed. Flushing a chain does not change the policy of the +chain, however. +.TP +.B "-Z, --zero" +Set the counters of the selected chain to zero. If no chain is selected, all the counters +are set to zero. The +.B "-Z" +command can be used in conjunction with the +.B "-L" +command. +When both the +.B "-Z" +and +.B "-L" +commands are used together in this way, the rule counters are printed on the screen +before they are set to zero. +.TP +.B "-L, --list" +List all rules in the selected chain. If no chain is selected, all chains +are listed. +.br +The following options change the output of the +.B "-L" +command. +.br +.B "--Ln" +.br +Places the rule number in front of every rule. This option is incompatible with the +.BR --Lx " option." +.br +.B "--Lc" +.br +Shows the counters at the end of each rule displayed by the +.B "-L" +command. Both a frame counter (pcnt) and a byte counter (bcnt) are displayed. +The frame counter shows how many frames have matched the specific rule, the byte +counter shows the sum of the frame sizes of these matching frames. Using this option +.BR "" "in combination with the " --Lx " option causes the counters to be written out" +.BR "" "in the '" -c " <pcnt> <bcnt>' option format." +.br +.B "--Lx" +.br +Changes the output so that it produces a set of ebtables commands that construct +the contents of the chain, when specified. +If no chain is specified, ebtables commands to construct the contents of the +table are given, including commands for creating the user-defined chains (if any). +You can use this set of commands in an ebtables boot or reload +script. For example the output could be used at system startup. +The +.B "--Lx" +option is incompatible with the +.B "--Ln" +listing option. Using the +.BR --Lx " option together with the " --Lc " option will cause the counters to be written out" +.BR "" "in the '" -c " <pcnt> <bcnt>' option format." +.br +.B "--Lmac2" +.br +Shows all MAC addresses with the same length, adding leading zeroes +if necessary. The default representation omits leading zeroes in the addresses. +.TP +.B "-N, --new-chain" +Create a new user-defined chain with the given name. The number of +user-defined chains is limited only by the number of possible chain names. +A user-defined chain name has a maximum +length of 31 characters. The standard policy of the user-defined chain is +ACCEPT. The policy of the new chain can be initialized to a different standard +target by using the +.B -P +command together with the +.B -N +command. In this case, the chain name does not have to be specified for the +.B -P +command. +.TP +.B "-X, --delete-chain" +Delete the specified user-defined chain. There must be no remaining references (jumps) +to the specified chain, otherwise ebtables will refuse to delete it. If no chain is +specified, all user-defined chains that aren't referenced will be removed. +.TP +.B "-E, --rename-chain" +Rename the specified chain to a new name. Besides renaming a user-defined +chain, you can rename a standard chain to a name that suits your +taste. For example, if you like PREFORWARDING more than PREROUTING, +then you can use the -E command to rename the PREROUTING chain. If you do +rename one of the standard ebtables chain names, please be sure to mention +this fact should you post a question on the ebtables mailing lists. +It would be wise to use the standard name in your post. Renaming a standard +ebtables chain in this fashion has no effect on the structure or functioning +of the ebtables kernel table. +.TP +.B "--init-table" +Replace the current table data by the initial table data. +.TP +.B "--atomic-init" +Copy the kernel's initial data of the table to the specified +file. This can be used as the first action, after which rules are added +to the file. The file can be specified using the +.B --atomic-file +command or through the +.IR EBTABLES_ATOMIC_FILE " environment variable." +.TP +.B "--atomic-save" +Copy the kernel's current data of the table to the specified +file. This can be used as the first action, after which rules are added +to the file. The file can be specified using the +.B --atomic-file +command or through the +.IR EBTABLES_ATOMIC_FILE " environment variable." +.TP +.B "--atomic-commit" +Replace the kernel table data with the data contained in the specified +file. This is a useful command that allows you to load all your rules of a +certain table into the kernel at once, saving the kernel a lot of precious +time and allowing atomic updates of the tables. The file which contains +the table data is constructed by using either the +.B "--atomic-init" +or the +.B "--atomic-save" +command to generate a starting file. After that, using the +.B "--atomic-file" +command when constructing rules or setting the +.IR EBTABLES_ATOMIC_FILE " environment variable" +allows you to extend the file and build the complete table before +committing it to the kernel. This command can be very useful in boot scripts +to populate the ebtables tables in a fast way. +.SS MISCELLANOUS COMMANDS +.TP +.B "-V, --version" +Show the version of the ebtables userspace program. +.TP +.BR "-h, --help " "[\fIlist of module names\fP]" +Give a brief description of the command syntax. Here you can also specify +names of extensions and ebtables will try to write help about those +extensions. E.g. +.IR "ebtables -h snat log ip arp" . +Specify +.I list_extensions +to list all extensions supported by the userspace +utility. +.TP +.BR "-j, --jump " "\fItarget\fP" +The target of the rule. This is one of the following values: +.BR ACCEPT , +.BR DROP , +.BR CONTINUE , +.BR RETURN , +a target extension (see +.BR "TARGET EXTENSIONS" ")" +or a user-defined chain name. +.TP +.B --atomic-file "\fIfile\fP" +Let the command operate on the specified +.IR file . +The data of the table to +operate on will be extracted from the file and the result of the operation +will be saved back into the file. If specified, this option should come +before the command specification. An alternative that should be preferred, +is setting the +.IR EBTABLES_ATOMIC_FILE " environment variable." +.TP +.B -M, --modprobe "\fIprogram\fP" +When talking to the kernel, use this +.I program +to try to automatically load missing kernel modules. +.TP +.B --concurrent +Use a file lock to support concurrent scripts updating the ebtables kernel tables. + +.SS +RULE SPECIFICATIONS +The following command line arguments make up a rule specification (as used +in the add and delete commands). A "!" option before the specification +inverts the test for that specification. Apart from these standard rule +specifications there are some other command line arguments of interest. +See both the +.BR "MATCH EXTENSIONS" +and the +.BR "WATCHER EXTENSIONS" +below. +.TP +.BR "-p, --protocol " "[!] \fIprotocol\fP" +The protocol that was responsible for creating the frame. This can be a +hexadecimal number, above +.IR 0x0600 , +a name (e.g. +.I ARP +) or +.BR LENGTH . +The protocol field of the Ethernet frame can be used to denote the +length of the header (802.2/802.3 networks). When the value of that field is +below or equals +.IR 0x0600 , +the value equals the size of the header and shouldn't be used as a +protocol number. Instead, all frames where the protocol field is used as +the length field are assumed to be of the same 'protocol'. The protocol +name used in ebtables for these frames is +.BR LENGTH . +.br +The file +.B /etc/ethertypes +can be used to show readable +characters instead of hexadecimal numbers for the protocols. For example, +.I 0x0800 +will be represented by +.IR IPV4 . +The use of this file is not case sensitive. +See that file for more information. The flag +.B --proto +is an alias for this option. +.TP +.BR "-i, --in-interface " "[!] \fIname\fP" +The interface (bridge port) via which a frame is received (this option is useful in the +.BR INPUT , +.BR FORWARD , +.BR PREROUTING " and " BROUTING +chains). If the interface name ends with '+', then +any interface name that begins with this name (disregarding '+') will match. +The flag +.B --in-if +is an alias for this option. +.TP +.BR "--logical-in " "[!] \fIname\fP" +The (logical) bridge interface via which a frame is received (this option is useful in the +.BR INPUT , +.BR FORWARD , +.BR PREROUTING " and " BROUTING +chains). +If the interface name ends with '+', then +any interface name that begins with this name (disregarding '+') will match. +.TP +.BR "-o, --out-interface " "[!] \fIname\fP" +The interface (bridge port) via which a frame is going to be sent (this option is useful in the +.BR OUTPUT , +.B FORWARD +and +.B POSTROUTING +chains). If the interface name ends with '+', then +any interface name that begins with this name (disregarding '+') will match. +The flag +.B --out-if +is an alias for this option. +.TP +.BR "--logical-out " "[!] \fIname\fP" +The (logical) bridge interface via which a frame is going to be sent (this option +is useful in the +.BR OUTPUT , +.B FORWARD +and +.B POSTROUTING +chains). +If the interface name ends with '+', then +any interface name that begins with this name (disregarding '+') will match. +.TP +.BR "-s, --source " "[!] \fIaddress\fP[/\fImask\fP]" +The source MAC address. Both mask and address are written as 6 hexadecimal +numbers separated by colons. Alternatively one can specify Unicast, +Multicast, Broadcast or BGA (Bridge Group Address): +.br +.IR "Unicast" "=00:00:00:00:00:00/01:00:00:00:00:00," +.IR "Multicast" "=01:00:00:00:00:00/01:00:00:00:00:00," +.IR "Broadcast" "=ff:ff:ff:ff:ff:ff/ff:ff:ff:ff:ff:ff or" +.IR "BGA" "=01:80:c2:00:00:00/ff:ff:ff:ff:ff:ff." +Note that a broadcast +address will also match the multicast specification. The flag +.B --src +is an alias for this option. +.TP +.BR "-d, --destination " "[!] \fIaddress\fP[/\fImask\fP]" +The destination MAC address. See +.B -s +(above) for more details on MAC addresses. The flag +.B --dst +is an alias for this option. +.TP +.BR "-c, --set-counter " "\fIpcnt bcnt\fP" +If used with +.BR -A " or " -I ", then the packet and byte counters of the new rule will be set to +.IR pcnt ", resp. " bcnt ". +If used with the +.BR -C " or " -D " commands, only rules with a packet and byte count equal to" +.IR pcnt ", resp. " bcnt " will match." + +.SS MATCH EXTENSIONS +Ebtables extensions are dynamically loaded into the userspace tool, +there is therefore no need to explicitly load them with a +-m option like is done in iptables. +These extensions deal with functionality supported by kernel modules supplemental to +the core ebtables code. +.SS 802_3 +Specify 802.3 DSAP/SSAP fields or SNAP type. The protocol must be specified as +.IR "LENGTH " "(see the option " " -p " above). +.TP +.BR "--802_3-sap " "[!] \fIsap\fP" +DSAP and SSAP are two one byte 802.3 fields. The bytes are always +equal, so only one byte (hexadecimal) is needed as an argument. +.TP +.BR "--802_3-type " "[!] \fItype\fP" +If the 802.3 DSAP and SSAP values are 0xaa then the SNAP type field must +be consulted to determine the payload protocol. This is a two byte +(hexadecimal) argument. Only 802.3 frames with DSAP/SSAP 0xaa are +checked for type. +.SS among +Match a MAC address or MAC/IP address pair versus a list of MAC addresses +and MAC/IP address pairs. +A list entry has the following format: +.IR xx:xx:xx:xx:xx:xx[=ip.ip.ip.ip][,] ". Multiple" +list entries are separated by a comma, specifying an IP address corresponding to +the MAC address is optional. Multiple MAC/IP address pairs with the same MAC address +but different IP address (and vice versa) can be specified. If the MAC address doesn't +match any entry from the list, the frame doesn't match the rule (unless "!" was used). +.TP +.BR "--among-dst " "[!] \fIlist\fP" +Compare the MAC destination to the given list. If the Ethernet frame has type +.IR IPv4 " or " ARP , +then comparison with MAC/IP destination address pairs from the +list is possible. +.TP +.BR "--among-src " "[!] \fIlist\fP" +Compare the MAC source to the given list. If the Ethernet frame has type +.IR IPv4 " or " ARP , +then comparison with MAC/IP source address pairs from the list +is possible. +.TP +.BR "--among-dst-file " "[!] \fIfile\fP" +Same as +.BR --among-dst " but the list is read in from the specified file." +.TP +.BR "--among-src-file " "[!] \fIfile\fP" +Same as +.BR --among-src " but the list is read in from the specified file." +.SS arp +Specify (R)ARP fields. The protocol must be specified as +.IR ARP " or " RARP . +.TP +.BR "--arp-opcode " "[!] \fIopcode\fP" +The (R)ARP opcode (decimal or a string, for more details see +.BR "ebtables -h arp" ). +.TP +.BR "--arp-htype " "[!] \fIhardware type\fP" +The hardware type, this can be a decimal or the string +.I Ethernet +(which sets +.I type +to 1). Most (R)ARP packets have Eternet as hardware type. +.TP +.BR "--arp-ptype " "[!] \fIprotocol type\fP" +The protocol type for which the (r)arp is used (hexadecimal or the string +.IR IPv4 , +denoting 0x0800). +Most (R)ARP packets have protocol type IPv4. +.TP +.BR "--arp-ip-src " "[!] \fIaddress\fP[/\fImask\fP]" +The (R)ARP IP source address specification. +.TP +.BR "--arp-ip-dst " "[!] \fIaddress\fP[/\fImask\fP]" +The (R)ARP IP destination address specification. +.TP +.BR "--arp-mac-src " "[!] \fIaddress\fP[/\fImask\fP]" +The (R)ARP MAC source address specification. +.TP +.BR "--arp-mac-dst " "[!] \fIaddress\fP[/\fImask\fP]" +The (R)ARP MAC destination address specification. +.TP +.BR "" "[!]" " --arp-gratuitous" +Checks for ARP gratuitous packets: checks equality of IPv4 source +address and IPv4 destination address inside the ARP header. +.SS ip +Specify IPv4 fields. The protocol must be specified as +.IR IPv4 . +.TP +.BR "--ip-source " "[!] \fIaddress\fP[/\fImask\fP]" +The source IP address. +The flag +.B --ip-src +is an alias for this option. +.TP +.BR "--ip-destination " "[!] \fIaddress\fP[/\fImask\fP]" +The destination IP address. +The flag +.B --ip-dst +is an alias for this option. +.TP +.BR "--ip-tos " "[!] \fItos\fP" +The IP type of service, in hexadecimal numbers. +.BR IPv4 . +.TP +.BR "--ip-protocol " "[!] \fIprotocol\fP" +The IP protocol. +The flag +.B --ip-proto +is an alias for this option. +.TP +.BR "--ip-source-port " "[!] \fIport1\fP[:\fIport2\fP]" +The source port or port range for the IP protocols 6 (TCP), 17 +(UDP), 33 (DCCP) or 132 (SCTP). The +.B --ip-protocol +option must be specified as +.IR TCP ", " UDP ", " DCCP " or " SCTP . +If +.IR port1 " is omitted, " 0:port2 " is used; if " port2 " is omitted but a colon is specified, " port1:65535 " is used." +The flag +.B --ip-sport +is an alias for this option. +.TP +.BR "--ip-destination-port " "[!] \fIport1\fP[:\fIport2\fP]" +The destination port or port range for ip protocols 6 (TCP), 17 +(UDP), 33 (DCCP) or 132 (SCTP). The +.B --ip-protocol +option must be specified as +.IR TCP ", " UDP ", " DCCP " or " SCTP . +If +.IR port1 " is omitted, " 0:port2 " is used; if " port2 " is omitted but a colon is specified, " port1:65535 " is used." +The flag +.B --ip-dport +is an alias for this option. +.SS ip6 +Specify IPv6 fields. The protocol must be specified as +.IR IPv6 . +.TP +.BR "--ip6-source " "[!] \fIaddress\fP[/\fImask\fP]" +The source IPv6 address. +The flag +.B --ip6-src +is an alias for this option. +.TP +.BR "--ip6-destination " "[!] \fIaddress\fP[/\fImask\fP]" +The destination IPv6 address. +The flag +.B --ip6-dst +is an alias for this option. +.TP +.BR "--ip6-tclass " "[!] \fItclass\fP" +The IPv6 traffic class, in hexadecimal numbers. +.TP +.BR "--ip6-protocol " "[!] \fIprotocol\fP" +The IP protocol. +The flag +.B --ip6-proto +is an alias for this option. +.TP +.BR "--ip6-source-port " "[!] \fIport1\fP[:\fIport2\fP]" +The source port or port range for the IPv6 protocols 6 (TCP), 17 +(UDP), 33 (DCCP) or 132 (SCTP). The +.B --ip6-protocol +option must be specified as +.IR TCP ", " UDP ", " DCCP " or " SCTP . +If +.IR port1 " is omitted, " 0:port2 " is used; if " port2 " is omitted but a colon is specified, " port1:65535 " is used." +The flag +.B --ip6-sport +is an alias for this option. +.TP +.BR "--ip6-destination-port " "[!] \fIport1\fP[:\fIport2\fP]" +The destination port or port range for IPv6 protocols 6 (TCP), 17 +(UDP), 33 (DCCP) or 132 (SCTP). The +.B --ip6-protocol +option must be specified as +.IR TCP ", " UDP ", " DCCP " or " SCTP . +If +.IR port1 " is omitted, " 0:port2 " is used; if " port2 " is omitted but a colon is specified, " port1:65535 " is used." +The flag +.B --ip6-dport +is an alias for this option. +.TP +.BR "--ip6-icmp-type " "[!] {\fItype\fP[:\fItype\fP]/\fIcode\fP[:\fIcode\fP]|\fItypename\fP}" +Specify ipv6\-icmp type and code to match. +Ranges for both type and code are supported. Type and code are +separated by a slash. Valid numbers for type and range are 0 to 255. +To match a single type including all valid codes, symbolic names can +be used instead of numbers. The list of known type names is shown by the command +.nf + ebtables \-\-help ip6 +.fi +This option is only valid for \-\-ip6-prococol ipv6-icmp. +.SS limit +This module matches at a limited rate using a token bucket filter. +A rule using this extension will match until this limit is reached. +It can be used with the +.B --log +watcher to give limited logging, for example. Its use is the same +as the limit match of iptables. +.TP +.BR "--limit " "[\fIvalue\fP]" +Maximum average matching rate: specified as a number, with an optional +.IR /second ", " /minute ", " /hour ", or " /day " suffix; the default is " 3/hour . +.TP +.BR "--limit-burst " "[\fInumber\fP]" +Maximum initial number of packets to match: this number gets recharged by +one every time the limit specified above is not reached, up to this +number; the default is +.IR 5 . +.SS mark_m +.TP +.BR "--mark " "[!] [\fIvalue\fP][/\fImask\fP]" +Matches frames with the given unsigned mark value. If a +.IR value " and " mask " are specified, the logical AND of the mark value of the frame and" +the user-specified +.IR mask " is taken before comparing it with the" +user-specified mark +.IR value ". When only a mark " +.IR value " is specified, the packet" +only matches when the mark value of the frame equals the user-specified +mark +.IR value . +If only a +.IR mask " is specified, the logical" +AND of the mark value of the frame and the user-specified +.IR mask " is taken and the frame matches when the result of this logical AND is" +non-zero. Only specifying a +.IR mask " is useful to match multiple mark values." +.SS pkttype +.TP +.BR "--pkttype-type " "[!] \fItype\fP" +Matches on the Ethernet "class" of the frame, which is determined by the +generic networking code. Possible values: +.IR broadcast " (MAC destination is the broadcast address)," +.IR multicast " (MAC destination is a multicast address)," +.IR host " (MAC destination is the receiving network device), or " +.IR otherhost " (none of the above)." +.SS stp +Specify stp BPDU (bridge protocol data unit) fields. The destination +address +.BR "" ( -d ") must be specified as the bridge group address" +.IR "" ( BGA ). +For all options for which a range of values can be specified, it holds that +if the lower bound is omitted (but the colon is not), then the lowest possible lower bound +for that option is used, while if the upper bound is omitted (but the colon again is not), the +highest possible upper bound for that option is used. +.TP +.BR "--stp-type " "[!] \fItype\fP" +The BPDU type (0-255), recognized non-numerical types are +.IR config ", denoting a configuration BPDU (=0), and" +.IR tcn ", denothing a topology change notification BPDU (=128)." +.TP +.BR "--stp-flags " "[!] \fIflag\fP" +The BPDU flag (0-255), recognized non-numerical flags are +.IR topology-change ", denoting the topology change flag (=1), and" +.IR topology-change-ack ", denoting the topology change acknowledgement flag (=128)." +.TP +.BR "--stp-root-prio " "[!] [\fIprio\fP][:\fIprio\fP]" +The root priority (0-65535) range. +.TP +.BR "--stp-root-addr " "[!] [\fIaddress\fP][/\fImask\fP]" +The root mac address, see the option +.BR -s " for more details." +.TP +.BR "--stp-root-cost " "[!] [\fIcost\fP][:\fIcost\fP]" +The root path cost (0-4294967295) range. +.TP +.BR "--stp-sender-prio " "[!] [\fIprio\fP][:\fIprio\fP]" +The BPDU's sender priority (0-65535) range. +.TP +.BR "--stp-sender-addr " "[!] [\fIaddress\fP][/\fImask\fP]" +The BPDU's sender mac address, see the option +.BR -s " for more details." +.TP +.BR "--stp-port " "[!] [\fIport\fP][:\fIport\fP]" +The port identifier (0-65535) range. +.TP +.BR "--stp-msg-age " "[!] [\fIage\fP][:\fIage\fP]" +The message age timer (0-65535) range. +.TP +.BR "--stp-max-age " "[!] [\fIage\fP][:\fIage\fP]" +The max age timer (0-65535) range. +.TP +.BR "--stp-hello-time " "[!] [\fItime\fP][:\fItime\fP]" +The hello time timer (0-65535) range. +.TP +.BR "--stp-forward-delay " "[!] [\fIdelay\fP][:\fIdelay\fP]" +The forward delay timer (0-65535) range. +.SS string +This module matches on a given string using some pattern matching strategy. +.TP +.BR "--string-algo " "\fIalgorithm\fP" +The pattern matching strategy. (bm = Boyer-Moore, kmp = Knuth-Pratt-Morris) +.TP +.BR "--string-from " "\fIoffset\fP" +The lowest offset from which a match can start. (default: 0) +.TP +.BR "--string-to " "\fIoffset\fP" +The highest offset from which a match can start. (default: size of frame) +.TP +.BR "--string " "[!] \fIpattern\fP" +Matches the given pattern. +.TP +.BR "--string-hex " "[!] \fIpattern\fP" +Matches the given pattern in hex notation, e.g. '|0D 0A|', '|0D0A|', 'www|09|netfilter|03|org|00|' +.TP +.BR "--string-icase" +Ignore case when searching. +.SS vlan +Specify 802.1Q Tag Control Information fields. +The protocol must be specified as +.IR 802_1Q " (0x8100)." +.TP +.BR "--vlan-id " "[!] \fIid\fP" +The VLAN identifier field (VID). Decimal number from 0 to 4095. +.TP +.BR "--vlan-prio " "[!] \fIprio\fP" +The user priority field, a decimal number from 0 to 7. +The VID should be set to 0 ("null VID") or unspecified +(in the latter case the VID is deliberately set to 0). +.TP +.BR "--vlan-encap " "[!] \fItype\fP" +The encapsulated Ethernet frame type/length. +Specified as a hexadecimal +number from 0x0000 to 0xFFFF or as a symbolic name +from +.BR /etc/ethertypes . + +.SS WATCHER EXTENSIONS +Watchers only look at frames passing by, they don't modify them nor decide +to accept the frames or not. These watchers only +see the frame if the frame matches the rule, and they see it before the +target is executed. +.SS log +The log watcher writes descriptive data about a frame to the syslog. +.TP +.B "--log" +.br +Log with the default loggin options: log-level= +.IR info , +log-prefix="", no ip logging, no arp logging. +.TP +.B --log-level "\fIlevel\fP" +.br +Defines the logging level. For the possible values, see +.BR "ebtables -h log" . +The default level is +.IR info . +.TP +.BR --log-prefix " \fItext\fP" +.br +Defines the prefix +.I text +to be printed at the beginning of the line with the logging information. +.TP +.B --log-ip +.br +Will log the ip information when a frame made by the ip protocol matches +the rule. The default is no ip information logging. +.TP +.B --log-ip6 +.br +Will log the ipv6 information when a frame made by the ipv6 protocol matches +the rule. The default is no ipv6 information logging. +.TP +.B --log-arp +.br +Will log the (r)arp information when a frame made by the (r)arp protocols +matches the rule. The default is no (r)arp information logging. +.SS nflog +The nflog watcher passes the packet to the loaded logging backend +in order to log the packet. This is usually used in combination with +nfnetlink_log as logging backend, which will multicast the packet +through a +.IR netlink +socket to the specified multicast group. One or more userspace processes +may subscribe to the group to receive the packets. +.TP +.B "--nflog" +.br +Log with the default logging options +.TP +.B --nflog-group "\fInlgroup\fP" +.br +The netlink group (1 - 2^32-1) to which packets are (only applicable for +nfnetlink_log). The default value is 1. +.TP +.B --nflog-prefix "\fIprefix\fP" +.br +A prefix string to include in the log message, up to 30 characters +long, useful for distinguishing messages in the logs. +.TP +.B --nflog-range "\fIsize\fP" +.br +The number of bytes to be copied to userspace (only applicable for +nfnetlink_log). nfnetlink_log instances may specify their own +range, this option overrides it. +.TP +.B --nflog-threshold "\fIsize\fP" +.br +Number of packets to queue inside the kernel before sending them +to userspace (only applicable for nfnetlink_log). Higher values +result in less overhead per packet, but increase delay until the +packets reach userspace. The default value is 1. +.SS ulog +The ulog watcher passes the packet to a userspace +logging daemon using netlink multicast sockets. This differs +from the log watcher in the sense that the complete packet is +sent to userspace instead of a descriptive text and that +netlink multicast sockets are used instead of the syslog. +This watcher enables parsing of packets with userspace programs, the +physical bridge in and out ports are also included in the netlink messages. +The ulog watcher module accepts 2 parameters when the module is loaded +into the kernel (e.g. with modprobe): +.B nlbufsiz +specifies how big the buffer for each netlink multicast +group is. If you say +.IR nlbufsiz=8192 , +for example, up to eight kB of packets will +get accumulated in the kernel until they are sent to userspace. It is +not possible to allocate more than 128kB. Please also keep in mind that +this buffer size is allocated for each nlgroup you are using, so the +total kernel memory usage increases by that factor. The default is 4096. +.B flushtimeout +specifies after how many hundredths of a second the queue should be +flushed, even if it is not full yet. The default is 10 (one tenth of +a second). +.TP +.B "--ulog" +.br +Use the default settings: ulog-prefix="", ulog-nlgroup=1, +ulog-cprange=4096, ulog-qthreshold=1. +.TP +.B --ulog-prefix "\fItext\fP" +.br +Defines the prefix included with the packets sent to userspace. +.TP +.BR --ulog-nlgroup " \fIgroup\fP" +.br +Defines which netlink group number to use (a number from 1 to 32). +Make sure the netlink group numbers used for the iptables ULOG +target differ from those used for the ebtables ulog watcher. +The default group number is 1. +.TP +.BR --ulog-cprange " \fIrange\fP" +.br +Defines the maximum copy range to userspace, for packets matching the +rule. The default range is 0, which means the maximum copy range is +given by +.BR nlbufsiz . +A maximum copy range larger than +128*1024 is meaningless as the packets sent to userspace have an upper +size limit of 128*1024. +.TP +.BR --ulog-qthreshold " \fIthreshold\fP" +.br +Queue at most +.I threshold +number of packets before sending them to +userspace with a netlink socket. Note that packets can be sent to +userspace before the queue is full, this happens when the ulog +kernel timer goes off (the frequency of this timer depends on +.BR flushtimeout ). +.SS TARGET EXTENSIONS +.SS arpreply +The +.B arpreply +target can be used in the +.BR PREROUTING " chain of the " nat " table." +If this target sees an ARP request it will automatically reply +with an ARP reply. The used MAC address for the reply can be specified. +The protocol must be specified as +.IR ARP . +When the ARP message is not an ARP request or when the ARP request isn't +for an IP address on an Ethernet network, it is ignored by this target +.BR "" ( CONTINUE ). +When the ARP request is malformed, it is dropped +.BR "" ( DROP ). +.TP +.BR "--arpreply-mac " "\fIaddress\fP" +Specifies the MAC address to reply with: the Ethernet source MAC and the +ARP payload source MAC will be filled in with this address. +.TP +.BR "--arpreply-target " "\fItarget\fP" +Specifies the standard target. After sending the ARP reply, the rule still +has to give a standard target so ebtables knows what to do with the ARP request. +The default target +.BR "" "is " DROP . +.SS dnat +The +.B dnat +target can only be used in the +.BR BROUTING " chain of the " broute " table and the " +.BR PREROUTING " and " OUTPUT " chains of the " nat " table." +It specifies that the destination MAC address has to be changed. +.TP +.BR "--to-destination " "\fIaddress\fP" +.br +Change the destination MAC address to the specified +.IR address . +The flag +.B --to-dst +is an alias for this option. +.TP +.BR "--dnat-target " "\fItarget\fP" +.br +Specifies the standard target. After doing the dnat, the rule still has to +give a standard target so ebtables knows what to do with the dnated frame. +The default target is +.BR ACCEPT . +Making it +.BR CONTINUE " could let you use" +multiple target extensions on the same frame. Making it +.BR DROP " only makes" +sense in the +.BR BROUTING " chain but using the " redirect " target is more logical there. " RETURN " is also allowed. Note that using " RETURN +in a base chain is not allowed (for obvious reasons). +.SS mark +.BR "" "The " mark " target can be used in every chain of every table. It is possible" +to use the marking of a frame/packet in both ebtables and iptables, +if the bridge-nf code is compiled into the kernel. Both put the marking at the +same place. This allows for a form of communication between ebtables and iptables. +.TP +.BR "--mark-set " "\fIvalue\fP" +.br +Mark the frame with the specified non-negative +.IR value . +.TP +.BR "--mark-or " "\fIvalue\fP" +.br +Or the frame with the specified non-negative +.IR value . +.TP +.BR "--mark-and " "\fIvalue\fP" +.br +And the frame with the specified non-negative +.IR value . +.TP +.BR "--mark-xor " "\fIvalue\fP" +.br +Xor the frame with the specified non-negative +.IR value . +.TP +.BR "--mark-target " "\fItarget\fP" +.br +Specifies the standard target. After marking the frame, the rule +still has to give a standard target so ebtables knows what to do. +The default target is +.BR ACCEPT ". Making it " CONTINUE " can let you do other" +things with the frame in subsequent rules of the chain. +.SS redirect +The +.B redirect +target will change the MAC target address to that of the bridge device the +frame arrived on. This target can only be used in the +.BR BROUTING " chain of the " broute " table and the " +.BR PREROUTING " chain of the " nat " table." +In the +.BR BROUTING " chain, the MAC address of the bridge port is used as destination address," +.BR "" "in the " PREROUTING " chain, the MAC address of the bridge is used." +.TP +.BR "--redirect-target " "\fItarget\fP" +.br +Specifies the standard target. After doing the MAC redirect, the rule +still has to give a standard target so ebtables knows what to do. +The default target is +.BR ACCEPT ". Making it " CONTINUE " could let you use" +multiple target extensions on the same frame. Making it +.BR DROP " in the " BROUTING " chain will let the frames be routed. " RETURN " is also allowed. Note" +.BR "" "that using " RETURN " in a base chain is not allowed." +.SS snat +The +.B snat +target can only be used in the +.BR POSTROUTING " chain of the " nat " table." +It specifies that the source MAC address has to be changed. +.TP +.BR "--to-source " "\fIaddress\fP" +.br +Changes the source MAC address to the specified +.IR address ". The flag" +.B --to-src +is an alias for this option. +.TP +.BR "--snat-target " "\fItarget\fP" +.br +Specifies the standard target. After doing the snat, the rule still has +to give a standard target so ebtables knows what to do. +.BR "" "The default target is " ACCEPT ". Making it " CONTINUE " could let you use" +.BR "" "multiple target extensions on the same frame. Making it " DROP " doesn't" +.BR "" "make sense, but you could do that too. " RETURN " is also allowed. Note" +.BR "" "that using " RETURN " in a base chain is not allowed." +.br +.TP +.BR "--snat-arp " +.br +Also change the hardware source address inside the arp header if the packet is an +arp message and the hardware address length in the arp header is 6 bytes. +.br +.SH FILES +.I /etc/ethertypes +.I @LOCKFILE@ +.SH ENVIRONMENT VARIABLES +.I EBTABLES_ATOMIC_FILE +.SH MAILINGLISTS +.BR "" "See " http://netfilter.org/mailinglists.html +.SH SEE ALSO +.BR iptables "(8), " brctl "(8), " ifconfig "(8), " route (8) +.PP +.BR "" "See " http://ebtables.sf.net |