search domain in resolv.conf is not appending to hosts when doing ping or other network communciation

Question

I am trying to find out why multiple search domains do not work with Debian 8.8.0. If you add the search domains in /etc/resolv.conf it will only work with one of them & in this case domain1.local works but domain2.local will not.

If you manually append the FQDN it works fine. This is for any and all CLI based tools: nslookup, ping, iperf, nmap, curl, wget ect. I have seen this before where Debian does not work with .local domains - and you have to remove avahi which I have already done to get the first .local domain working: domain1.local.

I have had multiple .local & other domain's working but with this version of Debian 8.8.x it is not working.

user@host:~$ uname -a
Linux host 3.16.0-4-amd64 #1 SMP Debian 3.16.43-2+deb8u2 (2017-06-26)     x86_64 GNU/Linux


user@host:~$ cat /etc/resolv.conf

nameserver 192.16.1.110
### Standard Search domains:
search domain1.local domain2.local domain3.local domain4.local

search domain - domain1 automatically appends the domain1.local and works for nslookup, ping ect.

user@host:~$ ping host1
PING host1.domain1.local (192.16.1.110) 56(84) bytes of data.
64 bytes from host1.domain1.local (192.16.1.110): icmp_seq=1 ttl=118    time=63.6 ms

user@host:~$ nslookup host1
Server:     192.16.1.110
Address:    192.16.1.110#53

Name:   host1.domain1.local
Address: 192.16.1.110

domain2 will not automatically be appended to the host (hosty) in this example. It will not find hosty with an nslookup from the dns server in /etc/resolv.fon (although it does exist). However - if you append the FQDN and run an nslookup, ping, curl,nmap,wget or any other cli based ip communication it works.

user@host:~$ nslookup hosty
;; Got SERVFAIL reply from 192.16.1.110, trying next server
;; Got SERVFAIL reply from 192.16.1.111, trying next server
Server:     192.16.1.110
Address:    192.16.1.110#53

** server can't find hosty: SERVFAIL

user@host:~$ ping hosty
ping: unknown host hosty

If we append domain2.local on the end of the host it can ping, nslookup, or other.

ping,nslookup & curl working with fqdn

user@host:~$ ping hosty.domain2.local
PING hosty.domain2.local (192.16.48.20) 56(84) bytes of data.
64 bytes from hosty.domain2.local (192.16.48.20): icmp_seq=1 ttl=119 time=63.6 ms

nslookup with fqdn:

user@host:~$ nslookup hosty.domain2.local
Server:     192.16.1.110
Address:    192.16.1.110#53

Name:   hosty.domain2.local
Address: 192.16.48.20

user@host:~$ curl hosty.domain2.local
curl: (7) Failed to connect to hosty.domain2.local port 80: Connection refused

It is worth mentioning that I have this identical configuration on a Ubuntu 16.04 workstation working with around 7 search domains.

The new Debian 8.8.x servers have the issue with working with more than 1 search domain. I must be missing some simple additional configuration that is required for Debian that is slightly different than Ubuntu.

Answer 1

Ok - so this was pretty oversighted of me but here was the issue. I had the domain1.local listed under the domain parameter in the /etc/resolv.conf

### Standard Search domains:
search domain1.local domain2.local
domain domain1.local # removed this line

After I ran the debug on nslookup and noticed that it was trying to append domain1.local for the nslookup I removed this and clearly it fixed the issue.

user@host:~$ nslookup hosty
Server:     192.16.1.110
Address:    192.16.1.110#53

Name:   hosty.domain2.local
Address: 192.16.48.20

Pretty stupid of me but just in case someone else makes the same mistake maybe this could help them.

Answer 2

From resolvconf manual, concerning dns-search

The dns-nameservers option is also accepted and, unlike dns-nameserver, can be given multiple arguments, separated by spaces. The dns-domain option is deprecated in favor of dns-search.

The resulting stanza might look like the following example.

iface eth0 inet static
    address 192.168.1.3
    netmask 255.255.255.0
    gateway 192.168.1.1
    dns-nameserver 192.168.1.254
    dns-nameserver 8.8.8.8
    dns-search foo.org bar.com

N.B.: On a machine where resolvconf has just been or is about to be installed and which previously relied on a static /etc/resolv.conf file,

• the nameserver information in that static file, (which is to say the information on nameserver, domain, search and sortlist lines) should be migrated to the appropriate iface stanza(s) in /etc/network/interfaces(5) as just described.

disclaimer: I usually delete network manager, resolvconf and systemd from my Debian servers.