Linux – Fail2ban blocking IP after unban

fail2baniptableslinux

I cant unban an IP from the server. I removed the address from fail2ban and deleted the entry from iptables, but I still can't login.

My Jail list name is sshd (checked with fail2ban-client status)

I did fail2ban-client set sshd unbanip <IP>

Then iptables -L -n --line-numbers had in Chain f2b-sshd a line to REJECT my IP.
I used iptables -D f2b-sshd <line_number> to delete my address from the iptables.

I still can't connect. The log /var/log/fail2ban.log contains
2019-04-12 13:37:40,963 fail2ban.filter [22791]: INFO [sshd] Found <IP> - 2019-04-12 13:37:40
Did I miss something? Why fail2ban says it found my IP after I unbanned?

Best Answer

You have to remove the ban using fail2ban, otherwise it will just re-add it. In your case it should be

fail2ban-client set f2b-sshd unbanip [banned IP address]

Related Solutions

Iptables – How to Unban an IP properly with Fail2Ban

With Fail2Ban before v0.8.8:

fail2ban-client get YOURJAILNAMEHERE actionunban IPADDRESSHERE

With Fail2Ban v0.8.8 and later:

fail2ban-client set YOURJAILNAMEHERE unbanip IPADDRESSHERE

The hard part is finding the right jail:

Use iptables -L -n to find the rule name...
...then use fail2ban-client status | grep "Jail list" | sed -E 's/^[^:]+:[ \t]+//' | sed 's/,//g' to get the actual jail names. The rule name and jail name may not be the same but it should be clear which one is related to which.

Iptables – fail2ban error on setting iptables on Synology NAS

Try so see what iptables modules are loaded on the good machine and compare them to the bad one:

# cat /proc/net/ip_tables_matches
state
icmp
recent
multiport
multiport
udplite
udp
tcp

Also check if the REJECT target exists:

# cat /proc/net/ip_tables_targets

REJECT
MASQUERADE
DNAT
SNAT
ERROR

If you do not see REJECT in the list, then your version of iptables does not have it and fail2ban rules will not be able to interact with it.

Best Answer

Related Solutions

Iptables – How to Unban an IP properly with Fail2Ban

Iptables – fail2ban error on setting iptables on Synology NAS

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