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Cannot ping outside UTM

I have tried and searched for two days and finally I relent and hope for help. I am setting up a UTM at home for the first time. I have looked over BAlfson's rulz and I am unable to get my setup off the ground.

Straightforward setup for testing.

Modem -> UTM -> Test PC

UTM External interface is pulling lease from Modem and  Internal is handling DHCP to Test PC without issues.

Masquerading rule setup for Internal(Network) -> External.

Internal network set to use UTM as DNS resolver and ISP assigned DNS forwarders is checked also tried with Google DNS servers.

Firewall rules initially set to allow only Internal -> Web Surfing -> Any and Internal -> DNS -> Any but have tried Internal ->Any ->Any

Disabled IPS and ATP for troubleshooting. Checked rulz noted logs.

Firewall logs are showing that every packet that is not of type UDP is being dropped. A long list of DNS request UDP packets will be allowed with sprinkled Default Drop TCP packets.

Any pointers or suggestions greatly appreciated. I am green in this area.



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  • Hi and welcome,

    is your modem in bridge mode?

    If you are using the UTM as the DNS, then you do not need an allow DNS rule, but make sure your internal network is in the allowed networks on the DSN.

    This might seem a dumb question, but did you enable the firewall rules?

    Ian

    XG115W - v20.0.2 MR-2 - Home

    XG on VM 8 - v21 GA

    If a post solves your question please use the 'Verify Answer' button.

  • Thanks for the response! I have the Internal network in the allowed networks and have made sure that the firewall rules are enabled. The modem is an Arris TM1602 provided by my ISP and from what I have read there is no configurations that can be done on it. I called my ISP to ask about MAC learning and leases, they said that it is just plug and play and that it will learn whatever MAC is plugged in and give it a lease and that there was no way to modify its operation. The modem gives my external interface an IP with no issues. I can ping between the two interfaces and the Test PC but cannot ping 8.8.8.8 even from UTM which I think must mean it is a routing issue and not DNS related? Or perhaps it is both. From my understanding a DNS issue alone would cause a site to be reachable via IP but not name? Forgive my naivety and thanks again for the reply.

  • Hi Doc,

    a DNS issue will not stop you being able to ping your site by IP address.

    From what you are saying is the modem is also a router and that is blocking your traffic because you cannot reach google DNS from the UTM. Try plugging a PC directly into the modem and see where you can get to?

    Ian

    XG115W - v20.0.2 MR-2 - Home

    XG on VM 8 - v21 GA

    If a post solves your question please use the 'Verify Answer' button.

  • Modem is just a modem no routing, if I plug directly into the modem I have connection as well as if I connect the ISP provided router back in. I had the UTM web filtering working fine bridged in full transparent mode behind the router before but now that I am switching to transparent and using the UTM as the default gateway these issues are arising. I am running out of ideas, I have tried four different NICs on the UTM and tested multiple devices in place of the original Test PC. I think at this point I will have to try re-installing UTM on the machine to see if a fresh install helps. Before I do that the last thing I am going to try (unless more is suggested)  is restoring the backups from before each update and see if there was something in one that caused the issues. I was a few releases behind so there were three that were done right in a row before I started setting up for the way it is now. 

    Thanks again, any further suggestions appreciated.

  • 1 what are the IPs for eth0 eth1? 
    2 It is there some ppoe configuration on the router
    3 it is marked your External WAN as Defaukt Gateway

  • Wow well I feel silly but thanks for pointing me in the right direction. I had specified the default gateway as the external ip in the internal but had not checked default Ipv4 gateway in the external.

    Thanks for the help, everything is working now!

  • DocSpiegel said:

    Wow well I feel silly but thanks for pointing me in the right direction. I had specified the default gateway as the external ip in the internal but had not checked default Ipv4 gateway in the external.

    Thanks for the help, everything is working now!

     

     

    Hi, could you specify more? I have the same problem. My UTM does all the internal stuff, but does not want to communicate with the outside world at all. Also, no pings possible from UTM to the internet. I guess i have a similar problem. 

  • Hi Chris,

    Does #3.1 in Rulz help?

    Cheers - Bob

     
    Sophos UTM Community Moderator
    Sophos Certified Architect - UTM
    Sophos Certified Engineer - XG
    Gold Solution Partner since 2005
    MediaSoft, Inc. USA
  • Show a printscreen of Masquerade and the wan connection.

    Mean time try to ping 8.8.8. from UTM