It sounds like you may have done a dist-upgrade from Debian Stretch to Debian Buster, but not updated Sympl at the same time?
Either way, if you run the Sympl installer without the --testing switch, it will swap you to the stable branch for the Debian version you’re running, which will then only take the relevant updates.
@Kelduum Great, it worked - eventually. When I ran the update yesterday it bombed then hung, broke the terminal sess. Unfortunately my notes, recall and the history got mangled so I can’t reproduce exactly, but here is where it failed at first in the event it says anything useful, Paul. Suffice to say it looks like it is all working, despite my efforts to break it. Thanks again.
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…
Recommended packages:
sympl-phpmyadmin
The following packages will be upgraded:
sympl-backup sympl-core sympl-firewall sympl-mail sympl-mysql
5 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
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…
Unpacking sympl-firewall (10.0.190816.0) over (10.0.190718.0) …
Preparing to unpack …/sympl-mysql_10.0.190731.0_all.deb …
I: Skipping removal.
W: /etc/mysql/my.cnf is not linked to either my.cnf.dpkg-sympl or my.cnf.dpkg-sympl-orig
Not removing diversion of /etc/mysql/my.cnf by sympl-mysql
Unpacking sympl-mysql (10.0.190731.0) over (10.0.190621.0) …
Setting up sympl-core (10.0.190908.0) …
I: Enabling dynamic MOTD
/usr/bin/sympl: line 175: 11555 Killed sudo apt-get -q -y install --only-upgrade ‘sympl-*’
$ sympl update
Reading package lists…
Building dependency tree…
Reading state information…
sympl-backup is already the newest version (11.20210818.1).
sympl-core is already the newest version (11.20220426.0).
sympl-cron is already the newest version (11.20220322.1).
sympl-dns is already the newest version (11.20210818.1).
sympl-firewall is already the newest version (11.20220719.0).
sympl-ftp is already the newest version (11.20210818.1).
sympl-mail is already the newest version (11.20220929.0).
sympl-monit is already the newest version (11.20210818.1).
sympl-mysql is already the newest version (11.20210818.1).
sympl-phpmyadmin is already the newest version (11.20210818.1).
sympl-updater is already the newest version (11.20210818.1).
sympl-web is already the newest version (11.20220406.0).
sympl-webmail is already the newest version (11.20220322.0).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Have you been using nftables, or had fail2ban, ufw or similar installed alongside sympl-firewall? Those are all ways to make things unhappy, and not supported configurations.
iptables (nftables drop-in replacement for iptables, default in Debian), iptables-legacy (the older iptables version, which Sympl uses) and nftables are effectively two different firewalls.
The best case is that they will both work normally, the worst case however is that neither will work.
You need to either use the sympl-firewall package only, or remove itr and mix-and-match as needed, but that’s not something that can be supported here.
I was under the (possibly mistaken) understanding that only iptables is installed in Debian 12 and that iptables-legacy is a soft link to the new firewall, provided for backward compatibility.