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DNS Server stops working for LAN Zones after Cisco VPN is established

DomNik

Hi all,

I've noticed the following issue while giving the Cisco VPN another try with Apple iOS on MR5:

After an IPsec connection is established from the internet which is configured to use the DNS server of the XG, it will work very fast and without any problems.

BUT all clients from the intranet which are configured to use the XG as a DNS server too, won't get any answers from the DNS server anymore. (and no FW logs)

The problem is solved after I a restart of the DNS server of the XG, while the first DNS request from the Cisco VPN client will break it again.

 

I'm using the XG's gateway IP of my first LAN Zone (separate network and vlan) as DNS server for my VPN setup. Exactly the same IPs and networks/ranges are working flawlessly (but slow) with L2TP on my iPhone.

Could this be a serious bug or am I missing something?

 

Thanks and best regards

DomNik



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  • 0

    Hi All,

    I am not able to discover any active case that relates to the issue. Alongside, Cisco VPN client is now obsolete but, as we have the functionality in the XG, I will test it and update further. Meanwhile, I would like to see the configuration for Cisco VPN and few lines from tcpdump to verify that a DHCP discover/request packet is not responded. 

    Thanks

Reply
  • 0

    Hi All,

    I am not able to discover any active case that relates to the issue. Alongside, Cisco VPN client is now obsolete but, as we have the functionality in the XG, I will test it and update further. Meanwhile, I would like to see the configuration for Cisco VPN and few lines from tcpdump to verify that a DHCP discover/request packet is not responded. 

    Thanks

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