How do you get dnsmasq to specify alternate DNS servers?

linux domain-name-system dhcp dnsmasq

86,443

Solution 1

Answered my own question, thanks to rfc2132

dhcp-option=6,192.168.0.90,192.168.0.98

However, RFC2132 specifies option 5 as a list of name servers and option 6 as a list of domain name servers, and I'm not sure what the difference is. Either way, option 6 put them correctly as

nameserver 192.168.0.90
nameserver 192.168.0.98

in /etc/resolv.conf

Solution 2

Posting as a separate answer rather than a comment on yours because that way I can use links.

Option 5 is for IEN 116 nameservers — a ridiculously obsolete protocol that Jon Postel wanted dead over twenty years ago. Solaris still supports it, but won't in the next version.

Solution 3

Another way is to set your dnsmasq server to be the DNS server for DHCP, and use /etc/resolv.conf on the dnsmasq server to specify your list of DNS servers. That way you can easily change DNS (and set aliases) without having to wait for DHCP renewal - just either restart or kill -HUP dnsmasq to reload the config.

86,443

vishnu

I graduated in June 2010 with a Bachelor of Engineering specializing in Computer Engineering from Carleton University in Ottawa, Ontario.

Updated on September 17, 2022

Comments

vishnu almost 2 years
I'm working on a network with ~10 kubuntu desktops (and numerous servers and IP phones) and am trying to get dnsmasq to specify another dns server as a failover. I tried using
```
server=192.168.0.90
```
but that just added the single dhcp/dns server to /etc/resolv.conf on my test machine (dynamic IP and freshly rebooted with no lease).
Admin over 10 years

Andrew, 'kill' command expects process identifier not process name. You should use either kill -HUP pidof dnsmasq or killall -HUP dnsmasq .
Tek about 8 years

@FeridMovsumov use server=8.8.8.8 in /etc/dnsmasq.conf
ceving almost 8 years

@Tek Google needs to know everything?
Tek almost 8 years

@ceving If not google then your ISP
AnthonyK over 4 years

For posterity: dnsmasq --help dhcp
Daniel Böhmer almost 4 years

This is the respective textual option which I prefer over opaque numbers like 6: dhcp-option=option:dns-server,...
Coroos over 3 years

DHCP option 5 is for IEN 116 style 'trivial name server daemon' (tnamed), see en.wikipedia.org/wiki/ARPA_Host_Name_Server_Protocol . Wasn't aware of its existance. Thanks for that!