Sophos altering packets causing timeouts

6710.dump.pcap.txt

Above are pics of current config and a tcpdump from the router during the aforementioned timeout.  File is in pcap format, remove the .txt extension.  the source port the steam service is using is 59580.  This issue did not show up until I upgraded from UTMv9.2 to UTMv9.4.

David, does #1 in Rulz give you any hints?

Cheers - Bob

Bob, thank you for responding.  This is a completely fresh install, no intrusion prevention, flood protection or portscan detection is turned on.

David, did you look at the log files?  I would have hoped for something in the firewall log.

Cheers - Bob

Yes, I have watched both the live logs for firewall and IPS (even though IPS is turned off), remains blank during the steamcmd execution, and logged in via SSH and search all the log files in /var/log for both the internal server IP and/or PORT and external server IP and/or PORT, nothing is found.

Hi David, 

I think your issue is associated with the MTU value 576, offered by the ISP modem. Refer the thread.

Thnaks

Sachingurun, thank you, I had noticed that from my ISP and tried changing the MTU before but it kept reverting.  I will try the fix in that article when I get home and let you all know the results.  Appreciate all the assistance.

Sachingurung,

The fix you provided worked perfectly!  I have also applied it to two other Sophos boxes that I manage and their connections problems have cleared as well.  Thank you again!

David

Hi David,

I am glad to hear that. 

Please contact us for any further assistance.

Thanks