Split-DNS problem

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nsumner

Posts: 3
Joined: Wed Jul 17, 2019 7:27 pm

Post by nsumner » Wed Jul 17, 2019 7:31 pm
I have encountered a repeatable problem with Split DNS.

I have 2 customers with OpenVPN AS servers.

Each connection on its own works perfectly. If I attempt to connect to both VPN servers at the same time then DNS breaks entirely.

I can't resolve any names, not on the specific VPNs, and not on the internet at large. The issue will be resolved when I disconnect BOTH VPN connections.

Eric Online

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Joined: Sun Jan 03, 2010 3:27 am

Post by Eric » Thu Jul 18, 2019 11:02 am
Hi nsumner,

This sounds like you may have a routing clash rather than a DNS problem. Are you able to ping servers beyond the VPN server for each connection? Are you able to resolve IPs directly using nslookup <FQDN> <server>?

If you'd like further assistance, could you please post a copy of both connection logs, and the output of route table and ipconfig after connecting both connections. As this potentially involves some sensitive information, you may with to email this to us instead as this is a public forum.

Regards,
Eric
Eric Thorpe
Viscosity Developer

Web: http://www.sparklabs.com
Support: http://www.sparklabs.com/support
Twitter: http://twitter.com/sparklabs

nsumner

Posts: 3
Joined: Wed Jul 17, 2019 7:27 pm

Post by nsumner » Mon Jul 22, 2019 8:38 pm
Sorry yes, I can absolutely ping the servers there is not an IP clash in this case. I can ping based on IP just DNS dies. And it fully dies. I also won't be able to ping www.google.com

Since they both are using split DNS this should not happen.

nsumner

Posts: 3
Joined: Wed Jul 17, 2019 7:27 pm

Post by nsumner » Mon Jul 22, 2019 8:59 pm
Sorry the nslookup fails as well. Where do I get the connection logs?

Eric Online

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Joined: Sun Jan 03, 2010 3:27 am

Post by Eric » Tue Jul 23, 2019 12:09 pm
Hi nsumner,

Here's how to view Viscosity's log - https://sparklabs.com/support/kb/article/viewing-the-openvpn-log/

Could you also send us a copy of your routing table after connecting both connections by typing 'route print' into a Command Prompt. This and your log may contain sensitive addresses, you may wish to email us instead at [email protected], please keep in mind this forum is public.

Regards,
Eric
Eric Thorpe
Viscosity Developer

Web: http://www.sparklabs.com
Support: http://www.sparklabs.com/support
Twitter: http://twitter.com/sparklabs
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