Mail Scanner blocking mails

[Arup]

My mail access started getting blocked by mail scanner as of yesterday, I use TB as client and have to turn off Avast's mail scanner to access all my mail servers and nntp.

Any reasons why all of a sudden this happened, haven't made any drastic changes to the system, I only use CHX as my inbound packet filtering firewall.

I checked with TCP View and for some reason, the mail scanner service refuses to activate although it is checked in Avast's control panel.

[vojtech]

"Mail scanner service refuses to activate" - can you explain ?
Is there any error message from TB ?

[Arup]

Nope, no messages, if I turn off the mail scanner service, it works fine.

I also found out that Avast Webshield interferes with HOST DHCP server and blocks dynamic DHCP client access as well, also webshield causes Kerio 2.15 to crash if used in conjunction with Treewalk which is a DNS server cum cacher program.