[BUG] Unable to connect minion to master - strange timeout

Hi everyone,

I've been dealing with a strange problem for a few weeks now, communication problem between a minion and the master. Communication timeout, while with a similar server it goes through ! Let me explain:

• My SALT MASTER server is in 192.168.1.100. Debian 11, Salt Master version 3005.
• My minion1 is on a different network in 192.168.10.0 /24. Debian 10.11, minion in version 3005. Minion1 has no problem to communicate with the Salt master, everything is ok.
• Minion2 is on the same network as Minion1. Debian 10.12, Salt Minion in 3005 too. And impossible to communicate with the master ...

What I've done so far:

• the network part is not the problem I think, I did pings/traceroute/nc at all times between the salt master and the minion2 and no worries. Moreover the minion1 is on the same network as the minion2 and has no problem
• I deleted on the master side the minion that is causing problems, and I deleted everything on the minion2 related to salt (configuration, packages etc). I reinstalled everything and redid the configuration as for the minion1, it does not change anything.
• Strange things: the minion2 communicates well with the salt master to register, I receive the key on the master. But then nothing, no more communication possible
• Second strange thing: I have exactly the same behavior if I deploy another server from scratch. Communication timeout

From Minion2 :

$ salt-call pillar.items
Unable to sign_in to master: Attempt to authenticate with the salt master failed with timeout error

From minion2 and /var/log/salt/minion file :

2022-09-09 16:09:25,573 [salt.minion      :1143][ERROR   ][877] Error while bringing up minion for multi-master. Is master at salt.xxx.org responding?

Again from minion2

[DEBUG   ] SaltEvent PUB socket URI: /var/run/salt/minion/minion_event_1a58a185c3_pub.ipc
[DEBUG   ] SaltEvent PULL socket URI: /var/run/salt/minion/minion_event_1a58a185c3_pull.ipc
[DEBUG   ] salt.crypt.get_rsa_pub_key: Loading public key
[DEBUG   ] Closing AsyncReqChannel instance
[ERROR   ] Error while bringing up minion for multi-master. Is master at salt.ozerim.fr responding?

From master log, nothing.

I don't know where to turn to correct this :(

If anyone has an idea, I'm interested!

Thanks !

Start by reproducing salt-call pillar.items on minion2 and reviewing /var/log/salt/minion alongside the master log. Compare minion1 and minion2 configurations and the registration-versus-authentication behavior. Done means the timeout cause is identified and minion2 can communicate with the master reliably.