Local DNS record only for selected VLANs?

Is it possible to create local DNS records only for some VLANs?

Please share your used case.

We have 4 VLANs and we want to create a local DNS record so that for instance somehost.atsomedomain.com is translated to a local IP address, but this must not be applied to devices of 1 VLAN.

Does the 1 VLAN that you don’t want to use local DNS resolution for this domain need to local dns resolution at all? Could it just use public DNS servers?

SIP & PBX scenario

We have 3 VLANs. On VLAN 30 the PBX.

SIP clients app can communicate with the PBX:

  • through the Internet using FQDN host with Inbound access & port mapping
  • in LAN using a (when connected to VLAN 10 & 20) with InterVLAN enabled

The problem is that under some circumstances the SIP client will attempt to connect through the Internet, although it is connected to VLAN 10/20 bringing in hairpinning issues. As this connection attempt is done through a FQDN host, if we can force a local DNS which will translate to the local PBX IP we will bypass the hairpinning issue. However the PBX must not use the local DNS described above, as it requires FQDN correct DNS translation to “advertise” it’s public IP address

So you want to implement split-horizon DNS, not sure there is really a sensible way to do this with the built in DNS proxy on Peplink.

Martin’s workaround is probably the only sensible path if you do not have the means to setup a “real” nameserver, give the clients in VLAN1 different DNS servers to talk to, either publicly accessible ones or some other device in your network that could forward DNS for them.

What is the PBX? If you can, set a local host file entry for the PBX FQDN and the public IP on the PBX itself. That will take priority over the local DNS servers it can use for all other queries.

Martin, it’s a telephone exchange central unit
Now that I think of it, we have a Microsoft DNS that could be used to force local IP address. and let the exempted VLAN to use google DNS to correctly address the FQDN

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