[Dnsmasq-discuss] setting up dynamic DNS?
adam.ant at cyberspaceroad.com
Mon Sep 10 12:14:29 BST 2007
Simon Kelley on 09/09/07 16:02, wrote:
> Adam Hardy wrote:
>> Hi DNSmasq List
>> I have a small network with a slightly different setup for the
>> internet broadband from usual. I'm having problems working out how to
>> set up a DHCP service with dnsmasq to provide workstations with
>> permanent host names.
>> Instead of the usual router providing DHCP and DNS services, I just
>> have a simple DSL modem attached to eth2 on my gateway server
>> (isengard). Using dhclient3, isengard grabs itself a public ip for
>> eth2 via DHCP on the modem.
>> isengard also runs dnsmasq on eth1 for the internal network, and I run
>> iptables as my firewall to protect it. I gave eth1 the IP 192.168.0.2
>> I have 2 more linux boxes, a windows machine and a mac, and the
>> potential for other random laptops to come and go. What I want to do
>> is set it up so that I can refer to boxes by their hostname at least
>> in linux wherever I am on the network, since I do alot of ftp'ing and
>> ssh'ing and I want to set up a samba share for backups and cups for
>> I've reached the point where dnsmasq tells every client to use
>> 192.168.0.2 as the nameserver. These clients run dhclient3 (and
>> windows and the mac are happy too)
>> But this naive approach obviously doesn't cut the mustard. Can I
>> instruct dnsmasq to be nameserver of all my hosts for each other?
>> Thanks and regards
>> Adam Hardy
>> PS this is the hosts and resolv.conf from one client:
>> adam at gondor:~$ cat /etc/hosts
>> 127.0.0.1 localhost gondor.localdomain.net gondor
>> adam at gondor:~$ cat /etc/resolv.conf
>> search localdomain.net
>> nameserver 192.168.0.2
>> and /etc/dhcp3/dhclient.conf:
>> send dhcp-lease-time 3600;
>> supersede domain-name "localdomain.net";
>> request subnet-mask, broadcast-address, time-offset, routers,
>> domain-name, domain-name-servers, host-name,
>> netbios-name-servers, netbios-scope, interface-mtu;
>> send fqdn.fqdn "gondor.localdomain.net";
>> send fqdn.encoded on;
>> send fqdn.server-update off;
>> isengard /etc/dnsmasq.conf:
> All your hosts are using dnsmasq as their nameserver, so once it knows
> the hostnames associated with particular DHCP leases, everything will
> just work.
> Broadly, there's two ways to do this. The first is to add names to the
> dnsmasq configuration, associating MAC addresses with names using
> dhcp-host configuration directives or in /etc/ethers. The second, and
> more common, is for the host to know its hostname, and send it to the
> DHCP server when it requests a lease: Windows (and, I'm fairly certain,
> Macs) do this always. dhclient3 needs to be told to do it with something
> send host-name "myname"
> in /etc/dhcp3/dhclient.conf. Some distros are clever and configure this
> automatically: most (still) don't. Sigh.
> STOP PRESS. Looking again, I see you're ahead of me, and sending the
> fqdn instead of the hostname. That should be fine, but you need to tell
> dnsmasq that "localdomain.net" is a valid network for it to accept for
> local hosts. Adding
> to /etc/dnsmasq.conf will do the trick.
Thanks for the responses, I've just tried again, but didn't succeed. I get 'name
or service unknown' response from ssh, ping etc.
I put in the "send host-name" option, as well as explicitly defining the
defaults for dhcp-option 1, 3 and 6.
Presumably if dnsmasq is meant to resolve/name-serve my clients, it will put
their hostnames in isengard's /etc/resolv.conf?
I am probably totally wide of the mark here, but isn't dhclient3 constantly
rewriting /etc/resolv.conf on isengard (gateway / dnsmasq server) to set up eth2
on the internet?
I am using the example dnsmasq.conf that came with the package, but I just
parsed out the comments. And unlike Jan, I'm not using pppoe so I'm not sure
what approach to take.
Thanks and regards
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