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Sophos firewall is blocking DNS queries
Posted: Sun Nov 11, 2012 5:31 pm
by aclawson
I'm working on the stake clerk machine at the moment, and DNS lookups are failing.
The DNS servers configured by the DHCP server (one of the new firewalls) are, in order
8.8.8.8
4.2.2.2
216.49.176.201
If I stop the service Sophos Client Firewall, DNS lookups work normally. If I restart the service DNS lookups stop working again.
Re: Sophos firewall is blocking DNS queries
Posted: Mon Feb 25, 2013 5:58 pm
by david.north
Were you able to resolve this problem outside of turning off the Sophos firewall?
We just experienced a similar problem this past Sunday on all three of the clerk computers in one building.
Re: Sophos firewall is blocking DNS queries
Posted: Tue Feb 26, 2013 7:38 am
by johnshaw
If you access the Sophos Firewall Logs through the management tool you should be able to see denies for port 53 and it will tell you which rule it is. If a rule has been pushed to Sophos we need to escalate it to the GSC and they can get in touch with someone who can get in touch with someone that will/may address the issue in the future at some point.
Re: Sophos firewall is blocking DNS queries
Posted: Tue Feb 26, 2013 9:13 am
by david.north
JohnShaw wrote:If you access the Sophos Firewall Logs through the management tool you should be able to see denies for port 53 and it will tell you which rule it is. If a rule has been pushed to Sophos we need to escalate it to the GSC and they can get in touch with someone who can get in touch with someone that will/may address the issue in the future at some point.
Great advice - I'll check the logs and let you know what I find.
Re: Sophos firewall is blocking DNS queries
Posted: Mon Mar 04, 2013 9:32 am
by aclawson
Did you see anything in the logs?
Re: Sophos firewall is blocking DNS queries
Posted: Mon Mar 04, 2013 9:36 am
by david.north
aclawson wrote:Did you see anything in the logs?
All applications were blocked because of an Invalid Checksum. Global support was unsure how to proceed, and recommended for our circumstance to allow all traffic through the Sophos Firewall and manually set DNS servers.
Re: Sophos firewall is blocking DNS queries
Posted: Mon Mar 04, 2013 10:09 am
by aclawson
Sophos is proving to be an unreliable choice. Unfortunately we're probably locked into an <x> year contract where <x> = 3-5 years.
Re: Sophos firewall is blocking DNS queries
Posted: Mon Mar 04, 2013 10:44 am
by russellhltn
dnorthut wrote:All applications were blocked because of an Invalid Checksum.
Sounds like uninstall/reinstall time. Local Unit Support can help you with that.