Set a specific reply address
glenn.satchell at uniq.com.au
Thu Apr 26 13:13:50 UTC 2012
> Is there a way to configure DHCPD to use a specific source IP
> address for replies? I have 4 IP addresses in my server and want to
> use one of them only for DHCP traffic. All the clients in my network
> are behind routers, which are relays pointing to the right IP address.
> The problem is that DHCPD is replying with the wrong IP address (the
> primary on the interface).
> Diego Woitasen
I think "server-identifier" might be what you want. It fills in the
server's IP address in the right field in the DHCP packet, so that clients
will reply to that address.
The server-identifier statement
The server-identifier statement can be used to define
the value that is sent in the DHCP Server Identifier
option for a given scope. The value specified must be
an IP address for the DHCP server, and must be reach-
able by all clients served by a particular scope.
The use of the server-identifier statement is not
recommended - the only reason to use it is to force a
value other than the default value to be sent on occa-
sions where the default value would be incorrect. The
default value is the first IP address associated with
the physical network interface on which the request
The usual case where the server-identifier statement
needs to be sent is when a physical interface has more
than one IP address, and the one being sent by default
isn't appropriate for some or all clients served by
that interface. Another common case is when an alias
is defined for the purpose of having a consistent IP
address for the DHCP server, and it is desired that the
clients use this IP address when contacting the server.
There is also "local-address" which changes the behaviour somewhat, but
may also help. Note that the code is in older versions, but was only added
to the man page more recently.
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