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Edward Tanguay
Asked: 2009-09-06 10:12:36 +0800 CST

What does it mean if one of the IP-addresses in my resolve.conf times out?

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Someone is helping me resolve a response time issue on my VPS.

He suggested I look in my resolv.conf and make sure neither of the IPs are timing out.

My resolve.conf looks like this:

nameserver 69.39.86.5
nameserver 69.39.89.9

when I do a nslookup on the second IP, it times out:

nslookup yahoo.com 69.39.86.9

  1. what does this tell me? do I need to inform my vps hosting provider of this?

  2. I noticed many resolv.conf examples on the web have the word "domain" or "search" followed by the domain name. Do I need that as well? My websites seem to work fine without it (domain name = tanguay.info).

domain

3 Answers

  1. What this means is that one of your DNS resolvers isn't working. You can probably just swap in OpenDNS/install your own nameserver.

    The 'search' line is a domain that's appended to names you lookup. So, if you have 

    search google.com

    in your resolv.conf, and you try to go to 'mail' you'll end up at 'mail.google.com'. It's not necessary, but is occasionally helpful

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  2. domain or search are mandatory if you want answers to not full qualified questions (at least one of both). If you always ask "yahoo.com", no need of domain or search.

    Concerning your secondary DNS, there may be a lot of causes : - DNS Server out of order, or DNS software out of order - You IP is blacklisted and the server don't answer you - Firewall behind you and the server. - Recursion not allowed in DNS and answer not in cache

    You can ask to your provider, but if it is a "big", he knows that a DNS is out.

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  3. Best Answer

    if its timing out, perhaps the DNS server is offline? What does this tell you? Well, it means if the primary server fails then your server will not be able to resolv any names aside form the hosts entries.

    As far as the domain or search followed by the domain name, its just telling your system that if you search for a name without the fully qualified domain name, it will first search in the said domain.

    As far as your website, it should function fine unless you have more than one server and are using DNS to resolv the ip address when they talk to each other, if thats the case, then you may have a problem if your main server goes down. However i'd recommend adding entries to the /etc/hosts file instead.

    PS, you can always use OPENDNS servers (opendns.com).

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