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SantaC
Asked: 2010-07-01 09:26:37 +0800 CST

DNS TTL problem

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So I have an external network card and an internal NIC on my windows 2008 R2 server. When I try to connect to some websites, i get a timeout which is a TTL problem. It goes away when i disable the internal NIC or disable RRAS, but i dont want to do that. I guess you need to configure something in RRAS but i dont know what. Does anyone have any idea? Micorsoft Diagnose says I have set it up correctly but yet something is wrong.

windows-server-2008 domain-name-system ttl

1 Answers

  1. Best Answer

    When you say "a TTL problem", I can't tell if you literally mean that you're seeing ICMP "time exceeded" messages (as a result of your IP datagrams being forwarded up to their TTL) or if you're trying to make some statement regarding DNS TTL values (which are a wholly different thing).

    I also can't tell if you're trying to say that this problem is happening on client computers or on the server computer itself. (Presumably you're trying to use your Windows Server 2008 R2 machine as the world's most expensive and cumbersome NAT router for some PCs...)

    Finally, you're talking about "connecting to web sites", which makes me think that you're not actually testing DNS lookup capabilities with nslookup (or some other tool), but rather are trying to use a browser to access web sites and interpreting the error message as being DNS-related.

    Are any of these statements accurate?

    It sounds to me like you've got a TCP/IP routing problem.

    The machine should have a single default gateway specified on the "outside" NIC only. Assuming it does, you should be able to PING the default gateway, and tracert to an Internet IP address should show packets leaving the machine and heading to the 'net via the default gateway.

    Once that works you can think about allowing clients to access the Internet via the NAT functionality of RRAS on the Windows Server machine. Microsoft has a basic how-to document that should guide you through the process. Until you've got basic IP connectivity on the server computer you're fighting a losing battle.

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