Re: NT 3.51 dhcp client and server ip address

[Ted Lemon <[e-mail]>]

> I have always believed this particular use was a tacit design decision of 
> the DHCP protocol.  It makes common sense and fits with the rest of the
> design of the protocol.  Any of you folks that have been around longer 
> than me remember any dicussion on the topic one way or the other?  Any 
> other client implementors not use the Server Identifier for the renewal 
> IP address?

There should be no tacit design decisions in a protocol specification.
If the server has multiple IP addresses, either because it is
multihomed, because it has aliases, or because it is operating on a
physical network with multiple logical subnets, there is no
unambiguous way to interpret the protocol specification.

It is not always safe to assume that one IP subnet is reachable from
another.   What if the DHCP server is also a firewall, but serves
clients on both sides of the firewall?   Which of the firewall's two
(or more) IP addresses should be used in the server identifier?

If the IP address of the interface through which the packet is being
sent must be used as the server identifier, then the specification
should say so.   There are very strong reasons for wanting to
use a consistent server identifier on a multi-homed DHCP server.   If
this is not permissible, or not recommended, the specification should
say so.

			       _MelloN_