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Alex Flo
Asked: 2014-03-28 01:59:06 +0800 CST

Debian resolver adds domain and I don't want that

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I have the following problem:
if I ping a non existent domain name I get a reply from an IP address
# ping nosuchdomain.common PING nosuchdomain.common.myrealdomain.com (192.168.1.1) 56(84) bytes of data. 64 bytes from myrealdomain.com (192.168.1.1): icmp_req=1 ttl=59 time=0.184 ms

Anyway, what I would want to happen would be to have the resolver work like this
#ping nosuchdomain.common ping: unknown host nosuchdomain.common

My /etc/resolv.conf looks like this now:
# nameserver config nameserver 8.8.8.8

Any idea where I should look to make the resolver return "unknown host"?

debian

2 Answers

  1. Normaly you should end a Domain Name with a dot, if you don't do this your resolver try to attach a search Domain from you network config (for example from DHCP)

    Your example with nosuchdomain.common should be written as nosuchdomain.common.

    To find out the reason where is set the search domain, you can use a static IP and set a different DNS Server and than you should not get a search domain. You should check you /etc/network/interfaces config for a search-domain parameter:

    #/etc/network/interfaces 
# The primary network interface
auto eth0
iface eth0 inet static
    address 192.168.1.100
    netmask 255.255.255.0
    gateway 192.168.1.1
    dns-nameservers 8.8.8.8
    dns-search myrealdomain.com
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  2. Thanks all for your suggestions, I accidentally found a solution to my problem and that is to explicitly add this line in /etc/resolv.conf
    search .com
    Once I did this it started working as expected.
    I guess the resolver has a default search as the domain of what is defined in /etc/hostname to which it adds whatever domain it cannot resolve directly.
    And as my DNS for this domain was configured with wildcard it explains why the made up domains were resolved to a certain IP.

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