I have a couple accounts that forward to external addresses and I am wondering if email sent to those accounts gets scanned for spam by spamassassin before being forwarded?
This is important because if not in the eyes for the external servers all that spam now appears to originate(in some respects) from my server.
If it doesn’t scan is there a way to address this?
Thanks
How did you setup the forwarding?
Depending on how the forwarding is setup – it may or may not get scanned first. If you set it up through Usermin (on port 20000), it should be scanned first in that case.
-Eric
Oh no I set it up in virtualmin. So I should delete it and recreate through usermin?
Yup, if you want it to run through SpamAssassin and ClamAV, you’d want to setup forwarding using Usermin.
-Eric
I never knew this. I’ve been dealing with my server getting on block lists for months! Does it make sense that spam being sent to an alias on my server and then forwarded unfiltered elsewhere could create a false positive that my server is the spamming server?
Thanks for the info. The new forwards have been set up. Not sure if they are working though.
Another question. What about greylisting? Would that work for all email regardless of how the forwarding is set up?
Does it make sense that spam being sent to an alias on my server and then forwarded unfiltered elsewhere could create a false positive that my server is the spamming server?
Hrm, that seems unlikely. It would normally require you to do more than forward spam from one account to another to end up on some sort of blacklist (such as sending email to their honeypot). However, many blacklists give you some details as to how you ended up on it.
What about greylisting? Would that work for all email regardless of how the forwarding is set up?
Greylisting would work for all incoming email, so that’s a good way to cut down on spam.
-Eric
i want to rebound on this one. Gmail is especialy bothering those last weeks and it would be great to have a way to filter forwarded emails even setup in the domain control panel 
best regards,
Ghislain.
Forwarding to Gmail or any other mail service was always a bad idea. In case you get hit by large amount of spam and that spam get forwarded to Gmail - Gmail will blacklist your IP because when forwarding your IP will be the sending one.
Much better solution is to use Gmail to retrieve emails from your server. Go to Settings - Accounts and import - Check mail from other accounts - and you can set 5 email accounts from where Gmail will pull the emails. This is much better solution than forward from your server. In case you have more than 5 email accounts on your server you could forward all those emails to one account and then set Gmail to pull from that account.
Gmail frequency to check for new emails depends on the amount of (new) emails you get, but usually its never longer than once per hour. Hotmail have similar option but i think you can set the frequency how often Hotmail will check for new emails. Probably other email services have similar solution.
Either way avoid forwarding emails to outside servers (Gmail, Hotmail…) because its bad practice and should be avoided when possible.