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DNS timeout after moving to VLAN tagged virtual interfaces

Hello,

I am encountering a strange issue with the Virginmedia name servers (192.168.4.100, 192.168.8.100).

I have just changed my network interface configuration on my Ubuntu machine to run two vlan tagged virtual interfaces via its single network interface card.

All works as expected with exception of the name servers where resolution requests are timing out. The name servers are responding correctly to requests from all other devices on the network (wired and wireless) and names are resolved as expected when using an alternate name server (e.g. 8.8.8.8). In addition, I have a windows 10 Virtual Box guest virtual machine bridged off the same interface; its DHCP assigned and both name servers are responding to requests to via the virtual machine two.

The only difference aside from the VLAN tagging between old and new configurations is static IP assignment in the new configuration vs reserved DHCP reserved in for the old config.

I hope I am missing something obvious because I think I can rule out a an issue with the Netgear switch and the NIC on my machine, I can rule out an issue with the name servers as they work for other devices and I think I can rule at an issue with the VLAN config the routing and name resolution works as expected for other services, I am perplexed. Any help or insights would be appreciated.

Old Config

(192.168.0.21 Ubuntu) (U - VLAN 1) 
    --> (Netgear SW GS716TV3) (U -VLAN 1) 
       --> (192.168.0.1 Hub 3.0)

New Config

(Ubuntu)
- 192.168.0.21 VLAN(1)
- 192.168.99.21 VLAN (99)
    --> (T) (Netgear SW GS716TV3) (U -VLAN 1)
      --> (192.168.0.1 Hub 3.0)

U = untagged packets, T = vlan tagged packets

 

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Alessandro Volta
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Re: DNS timeout after moving to VLAN tagged virtual interfaces

Its a mistake everyone makes for VM DNS:

They are:

194.168.4.100

194.168.8.100

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Re: DNS timeout after moving to VLAN tagged virtual interfaces

Thank you, I feel very silly now 😄

I did wonder why they it was an internal IP address.

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