iptables-translate -A FORWARD -p esp -j ACCEPT
nft 'add rule ip filter FORWARD ip protocol esp counter accept'

iptables-translate -A INPUT  --in-interface  wan --protocol esp -j ACCEPT
nft 'add rule ip filter INPUT iifname "wan" ip protocol esp counter accept'

iptables-translate -A INPUT -p 50 -m esp --espspi 500 -j DROP
nft 'add rule ip filter INPUT esp spi 500 counter drop'

iptables-translate -A INPUT -p 50 -m esp --espspi 500:600 -j DROP
nft 'add rule ip filter INPUT esp spi 500-600 counter drop'