Re: hostname of remote computer
On Sun, 31 Oct 2010 20:17:05 -0600,
Bob Proulx <bob@proulx.com> wrote:
[...]
> I assume the laptop gets a dynamic address from DHCP and doesn't
> register a dynamic DNS address for it?
My understanding of these terms is very limited, but I think so.
> If you only need this for ssh then you can add an entry in your ssh
> configuration file ~/.ssh/config similar to this one:
> Host foo.example.com
> Hostname 192.0.32.10
> HostKeyAlias foo.example.com
> And if you don't want to type in the full name you can set up a short
> hostname for it too.
> Host foo
> Hostname 192.0.32.10
> HostKeyAlias foo.example.com
>> As per the man page, /etc/hosts has:
>> IP_address canonical_hostname [aliases]
> That means something like this:
> 192.0.32.10 foo.example.com foo bar
> The IP address is first on the line. The next entry is taken as the
> fully qualified domain name when converting from IP address to name.
> Any additional entries on the line are taken as additional aliases.
> Note that the FQDN (fully qualified domain name) does not mean the
> canonical name. I know the man page says that but times have changed.
>> To get the canonical_hostname I thought I'd easily get it by typing
>> "dnshostname" when logged into the remote laptop, but that returns
>> nothing, and "domainname" returns '(none)'. How should this
>> canonical_hostname be specified in this case?
> Normally you would look up the IP address in DNS and see what PTR
> record is returned for it. That name is typically the canonical
> hostname.
> $ host quantz.debian.org quantz.debian.org has address 206.12.19.122
> $ host 206.12.19.122 122.19.12.206.in-addr.arpa domain name pointer
> quantz.debian.org.
> So here we would say that the canonical name is quantz.debian.org but
> it does also have other names.
> $ host qa.debian.org qa.debian.org has address 206.12.19.122
> But many hosts don't really have canonical hostnames anymore. Not
> since the addition of dual homed or multi-networked hosts with
> potentially several IP addresses possibly on each network interface
> not to mention VPN addresses. Because then it is possible for a host
> to have multiple names in the reverse DNS for the different IP
> addresses. So with that in mind a host really doesn't have one single
> canonical name in many cases. But when it does that is what we call
> it.
Thanks very much!! This has been very instructive.
--
Seb
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