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Random clients losing ability to connect to UTM

Hi all,

This is truly a weird one and I hope you can help me find a solution.

We have 2 ASG525's running in active-passive HA. Last night I updated one to 9.353-4 but this problem was occurring on the previous version over the last week, I was hoping the update would solve it :( 

The bulk of our 1200 users are working fine but we have been getting an increasing number of reports of a machine that cannot connect to the external Internet. When these users call up the help-desk guys have been verifying that they can connect to internal resources (Intranet, LMS etc) all correctly and they have lost all external access. Today, I have been working on a number of these devices to try and work out the cause, a reboot fixes them but that is not really a solution as it is becoming more regular.

A machine that is not working say has an IP address of 192.168.2.1 and the firewall has an address of 192.168.1.1. My machine has an address of 192.168.2.2.

From my machine I can ping the firewall but cannot ping the affected client.

From the firewall I can ping my machine but not the affected client.

From the core switch I can ping all 3 devices.

From my machine I can traceroute to google.com successfully.

From the affected machine the traceroute to google.com fails as soon as it hits the vlan address of the core switch.

From the firewall I can traceroute to my machine and google.com but not the affected machine.

From the core switch I can traceroute successfully to everything mentioned here.

I have tried to clear the ARP and route cache from the CLI of the UTM. I have tried to clear the ARP cache on the core switch. I have tried to reset every toggle switch possible in the UTM as the problem is occuring but nothing except an interface disconnect (or reboot) gets that machine to start making external connections once again.

Anyone got any ideas to help with this one?

Cheers,

Brendan



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  • I currently am having a similar issue, have already opened a support case, and they have not really seamed to be able to help much so far. I have the issue where the client will get the message unable to connect to proxy server, I can ping the client from any other internal LAN computer, the client can ping all other internal lan devices such as AD dhcp servers etc. but the client pc will not be able to ping the UTM. As soon as I ping the client that has the issue from the support tools ping tool in the UTM the client immediately has external access again. I have one laptop that it happens to just about everyday, the others are just random PC's through out the network. A user can be using the PC and on the internet and then it will get the message unable to connect to proxy server. I am using a UTM320 with the latest firmware.
  • Sounds very similar! Please let me know if you hear anything from support that is helpful.

    I have only had 1 reply from support so far, no ideas or resolutions, just asking me for more packet captures next time the issue occurs today...
Reply Children
  • Well we ended up restarting the http proxy services from the shell and so far we have not had any issues this week after doing this, so we will see. Not sure how that would be any different from just rebooting the UTM which I did several times and still had the issue.

  • Interesting. One should be able to achieve the same effect by disabling and then enabling web filtering from within WebAdmin.

    Cheers - Bob
     
    Sophos UTM Community Moderator
    Sophos Certified Architect - UTM
    Sophos Certified Engineer - XG
    Gold Solution Partner since 2005
    MediaSoft, Inc. USA
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