Possible firewall problem?

Kerodo · 2004-08-29T02:21:09+00:00

I'm noticing an occasional entry in my firewall logs and I'm not sure if it's a problem or not. I'm seeing a 40 byte TCP packet going outbound from my local port 25 to a remote port (seems to change, but last one was 4043). The remote IP address doesn't look familiar. Seems to be just a random address somewhere. In the info column of the logs, it just says TCP flags: RST ACK.Could this indicate that packets are somehow getting thru the firewall and my system is responding with an outbound packet like this? The firewall is blocking the outbound packet. I'm just wondering what is causing it in the first place..

Aug 29, 2004 22 Replies

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Copelandia Cyanescens 22 years ago

See below...

Yes. Perfect sense. ;) I should have realized this right from the start, but Avast is functioning as a "proxy", intercepting outgoing mail (port

25), incoming mail (port 110), and IMAP mail (port 143), so that it can scan said mail for viruses. The 127.0.0.1 means it's only allowing connections from your machine (localhost), but it's possible that your firewall simply allows that application free rein to connect, and relies on Avast to accept or reject connections based on its own criteria.

There's really nothing at all fishy with this. After realizing what's going on I can't see any other way to do it.

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optikl 22 years ago

Desirable? Well, it's another layer of protection beyond simple packet filtering. Important? Depends on you and whether or not your computing practices are safe enough without it.

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