Possible SMTP DoS attack?

[sparky]

Hmm..... I guess no one has any answers for me for why my server's being so weird??

It's actually ok now in the fact that I am not getting the resources filled with people trying to connect through it, but I still can't send any mail through port 25 :-(

Secure port is fine though

[uxbod]

Can you telnet on port 25 to a remote MTA ?

[sparky]

Yep no probs.....

My concern though is with MUA's! Thunderbird won't connect to my server??

Currently I am connecting through port 465, before I used to be able to connect on port 25 via Seamonkey to send email......

[uxbod]

I presume from the workstation where the MUA is installed you can telnet to port 25 on your ZCS server ? when your MUA does attempt a connection anything showing in your ZCS logfiles ?

[veronica]

Do you use any RBL service ? It is always beneficial as 70% of spam traffic is removed at initial client connection stage. This will help to keep your worker threads free for legitimate traffic