fail2ban, Debian buster/10 and iptables vs nftables

Buster forces a move to nftables, unfortunately fail2ban thinks it’s still using iptables, so nothing gets blocked. To fix ….

(fail2ban in Buster also seems to require systemd – and no longer reads from e.g. /var/log/mail.log, which is a bit disappointing but oh well…)

After messing about trying to get nftables working – where trying to use the default /etc/nftables.conf file just results in an error a bit like :

/etc/nftables.conf:6:15-19: Error: Could not process rule: No such file or directory
chain input {

I gave up, and found the Debian Wiki Page which gives :

update-alternatives --set iptables /usr/sbin/iptables-legacy
update-alternatives --set ip6tables /usr/sbin/ip6tables-legacy
update-alternatives --set arptables /usr/sbin/arptables-legacy
update-alternatives --set ebtables /usr/sbin/ebtables-legacy

Which now allows fail2ban to actualy block things (via /var/log/fail2ban.log etc).


  1. Thanks – no I hadn’t seen that page before.

    I’ve been finding that fail2ban is of less use over time – as more and more attacks are becoming properly distributed.

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