[Dnsmasq-discuss] Setting dns domain name through dhcpv6
Roy Marples
roy at marples.name
Sat Mar 8 14:10:56 UTC 2014
On 08/03/2014 12:07, Tom Hendrikx wrote:
> I was already using the search option, but it was giving me some
> headaches, mainly because what I actually was trying to get to work
> was that 'hostname --fqdn' on the client would actually return the
> correct fqdn from the dhcp network.
AFAIK that has nothing todo with either search or domain options in
resolv.conf.
hostname --fqdn queries the nameservers to work out what the FQDN is
based on your IP address.
This is also quite erroneous. Here's the Linux man page section:
==========================
the Fqdn
You can't change the FQDN (as returned by hostname --fqdn) or the DNS
domain name (as returned by dnsdomainname) with this command. The FQDN
of the system is the name that the resolver(3) returns for the host
name.
Technically: The FQDN is the name gethostbyname(2) returns for the host
name returned by gethostname(2). The DNS domain name is the part after
the first dot.
Therefore it depends on the configuration (usually in /etc/host.conf)
how you can change it. Usually (if the hosts file is parsed before DNS
or NIS) you can change it in /etc/hosts.
If a machine has multiple network interfaces/addresses or is used in a
mobile environment, then it may either have multiple FQDNs/domain names
or none at all. Therefore avoid using hostname --fqdn, hostname --domain
and dnsdomainname. hostname --ip-address is subject to the same
limitations so it should be avoided as well.
==========================
As such, hostname should either be a single name (foo) or a FQDN
(foo.bar.com) and the hostname program shouldn't do any DNS lookups at
all.
That is what we have tools such as host(1) and dig(1) for.
Roy
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