So I am using Gajim. Suppose I have two contacts and I use separate accounts to chat with each one. We are all on the same XMPP server using OMEMO. Can my two accounts be correlated to both be the same user (me )? Do things get isolated somehow ? Or do I have to make sure only one account is ‘available’ at same time, and reset Tor to get a new IP for each chat session ?
From what i understand, the way DNS is routed with Gajim is that always has to go through the TransPort.
What this means effectively, is that all connections will route their dns queries through the same port.
This is not a limitation on Whonix’s end but rather this is an issue with python and the way that proxys would have to be configured to be completely stream isolated. It is a coding issue that would have to be resolved by gajim developers. This does not seem likely however
For your situation taking into consideration what was said above, to be absolutely sure you avoid correlation only use one account at a time. And only one account per Tor session. Of course there are other things to take into consideration like timing of when you use the accounts ie. you finish one and end the Tor session, and then a couple minutes later you start the other one now on a fresh session but maybe you use the same way of speaking or reference the same things the other account talks about; really just common sense stuff.
Best advice: use one at a time