isc-dhcpd server, HOSTNAME
Pieter.Donche at ua.ac.be
Tue May 12 07:52:25 UTC 2009
On Sun, 10 May 2009, Matthew Seaman wrote:
> Pieter Donche wrote:
>> FreeBSD7 with isc-dhcp30-server.
>> It hands out an IP address, OK,
>> but the BASH environment variable HOSTNAME is not set. Why?
>> (A DNS server is active on the network and can succesfully be queried from
>> a FreeBSD bash command (nslookup or host) to see the hostname associated
>> with the IP-address)
> Hostname is not one of the parameters usually requested from a DHCP server
> by a Unix machine. In fact, it's normally the other way round: the client
> tells the DHCP server what it's hostname is and the DHCP server can then
> inject an A record into the DNS dynamically.
So, the normal way is that you have an entry hostname="somename.somedomain"
in /etc/rc.conf ?
I can't remember the details of the install of this FreeBSD7 system, set up
as a DHCPclient, but is during the installation the name of the host you want
this machine to have and its domainname something that is asked for?
(and then recorded in /etc/rc.conf)
> However it is possible to operate in the way you want. To tell the dhcp
> server to look up names from the DNS based on the address supplied to a
> host, search for the description of the 'get-lease-hostnames' flag in
> the dhcpd.conf(5) man page.
> To tell dhcp clients to fetch their hostname from DHCP, you need to add it
> to a 'request' or 'require' block in dhclient.conf -- see dhclient.conf(5).
> It's been a long time since I ran a setup anything like that, so I cannot
> recall if that was all that was required, or if it was also necessary to
> write a small dhclient-script(8) to actually set the hostname.
> Another alternative is to use a dhclient-script to take the IP number
> allocated by the DHCP server, look up the corresponding address and then
> set that as the hostname.
> The bash HOSTNAME environment variable will be set from the output of the
> hostname(1) command, which is usually set from the hostname variable in
> /etc/rc.conf or from the output of '/bin/kenv dhcp.host-name' if that is set.
> Otherwise it uses a default hostname of 'amnesiac'.
> Dr Matthew J Seaman MA, D.Phil. 7 Priory Courtyard
> Flat 3
> PGP: http://www.infracaninophile.co.uk/pgpkey Ramsgate
> Kent, CT11 9PW
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