How to resolve "No chain/target/match by that name" when using iptables-multiport and Fail2Ban
This issue isn't specifically related to Fail2Ban but is a common way for it to present itself.
The Fail2Ban log output will show something similar to:
2020-06-22 16:18:09,356 fail2ban.actions [17988]: ERROR Failed to execute ban jail 'sasl' action 'iptables-multiport' info 'ActionInfo({'ip': '1.2.3.4',