Multiple next-servers ?
Glenn.Satchell at uniq.com.au
Tue Sep 4 11:55:54 UTC 2007
>From: Richard Offer <offer at fastscale.com>
>To: "dhcp-users at isc.org" <dhcp-users at isc.org>
>Date: Mon, 3 Sep 2007 17:40:21 -0700
>Subject: Multiple next-servers ?
>Is it possible to list multiple next-servers for use in a HA environment ?
>The docs seem ambiguous neither including or precluding it ?
If you go to RFC2131 it's not ambiguous. There is one 4 byte field
available for siaddr (which is what next-server sets).
In dhcpd.conf man page, there is no mention that more than one address
can be supplied:
The next-server statement
The next-server statement is used to specify the host
address of the server from which the initial boot file
(specified in the filename statement) is to be loaded.
Server-name should be a numeric IP address or a domain
Here is an example, from dhcp-options man page, that accepts multiple
option domain-name-servers ip-address [, ip-address... ];
However, you can define different a next-server in different scopes if
One model is that if you use failover, then each dhcp server refers to
itself as the next-server. That way if the other server is down it won't
try and direct clients to that system.
Alternatively you could use a floating IP address that gets moved
between servers - this is the linux-ha model (and others).
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