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[mydns]

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Mazarin
Mazarin W/ Alumni Posts: 2 Security Scout

How F-Secure firewall determines [mydns] definition in firewall rules? It happens to me that F-Secure Firewall denies connection to one of two DNS servers while I am using VPN. So I would like to know more what is laying behind [mydns] logic. Thanks!

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  • Vad
    Vad W/ Alumni Posts: 1,069 Cybercrime Crusader
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    Hello Mazarin,

     

    [mydns] actually means ip address 172.16.0.3.

     

    Best regards,

    Vad

  • Mazarin
    Mazarin W/ Alumni Posts: 2 Security Scout
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    Why 172.16.0.3? It doesn't make sense. I would rather expect that [mydns] is dynamically assigned by IP addresses of DNS servers according to actual TCP/IP configuration. But in that case, why f-secure fw denies name resolving to one of the DNS servers while I'm using VPN. I'm afraid there is a bug behind [mydns] logic.

     

    Previously I have this FW rule for DNS:

    localmachine -> [mydns] via TCP/UDP 53

     

    To assure that both DNS servers are accessible for DNS resolving while I'm using VPN I have to replace the rule by this:

    localmachine -> 0.0.0.0/0 via TCP/UDP 53

     

    But I'm sill curious how [mydns] in F-Secure works.

  • Vad
    Vad W/ Alumni Posts: 1,069 Cybercrime Crusader
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    Mazarin, you are right. I'm sorry for incorrect answer. [mydns] is dynamically changing list of DNS servers. The list is updating every time when FW checks the rule.

     

    What product/version do you have?

    If you think it doesn't work as expected, please, contact support. We will need more detailed information and probably debug logs from affected machine.

     

    Best regards,

    Vad

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