Multi LAN DNS - Deny cross-LAN Name Resolution



  • I have added a second LAN to my network. The idea is to keep the two separate. I haven't setup any routing between them and they are on two different physical interfaces.

    My question is about DNS resolution. I already have setup the DNS resolver for the local machines on my original LAN. I don't want the second LAN to have these hostnames resolved.

    Under the DNS resolver access list setting, the options are:

    • Deny: Stops queries from hosts within the netblock defined below.`
    • Refuse: Stops queries from hosts within the netblock defined below, but sends a DNS rcode REFUSED error message back to the client.`
    • Allow: Allow queries from hosts within the netblock defined below.`
    • Allow Snoop: Allow recursive and nonrecursive access from hosts within the netblock defined below. Used for cache snooping and ideally should only be configured for the administrative host.
    • Deny Nonlocal: Allow only authoritative local-data queries from hosts within the netblock defined below. Messages that are disallowed are dropped.
    • Refuse Nonlocal: Allow only authoritative local-data queries from hosts within the netblock defined below. Sends a DNS rcode REFUSED error message back to the client for messages that are disallowed.

    What I actually am looking for would seem to be:

    • Deny Local - Allow only authoritative non-local-data queries from hosts within the netblock defined below. Messages that are disallowed are dropped.

    I want the DNS resolver to respond, but only with non-local hosts. Is it possible to do this?

    Or would it be better to not allow the DNS resolver on that interface, and just have the DHCP server give out WAN DNS servers?


  • Rebel Alliance Global Moderator

    So you want these clients to only resolve public stuff and nothing local?

    Then you would point them to an outside dns... You wouldn't even let them talk to your local dns. Zero point.. let them talk to googledns if all you want them to do is resolve public stuff.



  • OK sounds good! Thanks for the tip.