path: root/doc/sync/notrack
diff options
authorPablo Neira Ayuso <>2008-11-18 10:33:33 +0100
committerPablo Neira Ayuso <>2008-11-18 10:33:33 +0100
commit6d8903cbf33ac10e8e03f884a58e374adc366887 (patch)
tree23c0ae1222a109b6d91da3377f6e7a91e81a4ce0 /doc/sync/notrack
parentd6f1b4be37e97dabb5de2d9ae664ef8afeec37ae (diff)
filter: choose the filtering method via configuration file
This patch changes the current behaviour of the filtering selection. Up to now, conntrackd has used the kernel version to select the filtering method based on the following logic: If kernel is >= 2.6.26 we use BSF-based filtering from kernel-space, otherwise, default to userspace. However, this filtering method still lacks of IPv6 support and it requires a patch that got into 2.6.29 to filter IPv6 addresses from kernel-space. To fix this issue, we default to user-space filtering and let the user choose the method via the configuration file. Signed-off-by: Pablo Neira Ayuso <>
Diffstat (limited to 'doc/sync/notrack')
1 files changed, 10 insertions, 2 deletions
diff --git a/doc/sync/notrack/conntrackd.conf b/doc/sync/notrack/conntrackd.conf
index 446e981..e9835e8 100644
--- a/doc/sync/notrack/conntrackd.conf
+++ b/doc/sync/notrack/conntrackd.conf
@@ -147,8 +147,16 @@ General {
# State. The filter is attached to an action that can be: Accept or
# Ignore. Thus, you can define the event filtering policy of the
# filter-sets in positive or negative logic depending on your needs.
- #
- Filter {
+ # You can select if conntrackd filters the event messages from
+ # user-space or kernel-space. The kernel-space event filtering
+ # saves some CPU cycles by avoiding the copy of the event message
+ # from kernel-space to user-space. The kernel-space event filtering
+ # is prefered, however, you require a Linux kernel >= 2.6.29 to
+ # filter from kernel-space. If you want to select kernel-space
+ # event filtering, use the keyword 'Kernelspace' instead of
+ # 'Userspace'.
+ #
+ Filter from Userspace {
# Accept only certain protocols: You may want to replicate
# the state of flows depending on their layer 4 protocol.