How do you get dnsmasq to specify alternate DNS servers?

Question

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).

score 37 · Accepted Answer · edited Oct 07 '21 at 07:34

37

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

edited Oct 07 '21 at 07:34

Community

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answered Jul 23 '10 at 19:45

pfyon

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Unfortunately /etc/resolv.conf refreshes after restart – Farid Movsumov Nov 20 '14 at 09:27
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@FeridMovsumov use `server=8.8.8.8` in /etc/dnsmasq.conf – Tek Mar 31 '16 at 04:43
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@Tek Google needs to know everything? – ceving Aug 07 '16 at 11:35
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@ceving If not google then your ISP – Tek Aug 07 '16 at 12:42
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For posterity: `dnsmasq --help dhcp` – AnthonyK Mar 22 '20 at 04:38
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This is the respective textual option which I prefer over opaque numbers like `6`: `dhcp-option=option:dns-server,...` – Daniel Böhmer Jul 30 '20 at 04:51
DHCP option 5 is for IEN 116 style 'trivial name server daemon' (tnamed), see https://en.wikipedia.org/wiki/ARPA_Host_Name_Server_Protocol . Wasn't aware of its existance. Thanks for that! – Coroos Oct 07 '20 at 08:07

score 9 · Answer 2 · edited Sep 02 '12 at 10:51

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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.

edited Sep 02 '12 at 10:51

alanc

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answered Jul 24 '10 at 04:51

Brad Ackerman

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score 1 · Answer 3 · answered Jul 24 '10 at 04:38

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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.

answered Jul 24 '10 at 04:38

Andrew

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Andrew, 'kill' command expects process identifier not process name. You should use either kill -HUP `pidof dnsmasq` or killall -HUP dnsmasq . – Mar 23 '14 at 07:44

How do you get dnsmasq to specify alternate DNS servers?

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