Win2k: RRAS + DHCP Service

  • Thread starter Thread starter Florian
  • Start date Start date
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Florian

Hi,

We're a bit puzzled since we want to accomplish what seems an easy thing. We
have a VPN server that people dial in from the Internet, works fine. It has
RRAS installed and setup as "Remote Access Server". It has one NIC.

Originally we had set it up to provide IP addresses from a pool, NOT using
the DHCP service. For various reasons though we need a DHCP service to
assign the RAS clients IP addresses, and not use the DHCP feature that RRAS
provides.

So I setup the DHCP service and it works well - except that it assigns IP
address also to clients on the local network LAN, where we want it to only
assign IP addresses to the RAS clients that come in through VPN/PPTP.

If I change the binding of the DHCP server (the machine has only one NIC)
then the RAS clients won't get IP addresses anymore, yet if I activate it
everybody gets IP addresses. I couldn't find any settings that would allow
me to do this - am I missing something?

Then I thought that I had the most brilliant idea - use the MS Loopback
Adapter. I installed it and configured the DHCP server to only listen on the
MS Loopback interface. Then I configured RRAS to send DHCP/BOOTP etc.
message using the Loopback Adapter only. Well, I thought this way I would
avoid assigning IP addresses to the clients yet being able to service the
RAS clients. Unfortunately this didn't work at all.

Does somebody have any other ideas on how this can be accomplished?


Thanks!
 
The RRAS clients do not get this info directly from DHCP. Because of the
way PPP/PPTP work, the client gets its IP address and name server addresses
from the RRAS server. This is part of the PPP/PPTP negotiation process. The
IP is allocated for the duration of the connection. If you select the DHCP
option in RRAS, the RRAS server leases a batch of IP addresses from DHCP to
use instead of using a static pool.

Where did your LAN clients get their IP addresses from before you set up
DHCP?
 
Thanks for the reply,

Well either way - the point is that we don't want the DHCP server to issue
IP addresses to the LAN, but only to the RRAS service. And that doesn't seem
possible - or is it?

Though I have to admit that I did not know that RRAS gets a batch of
addresses - I thought this was just passed through.

There is another DHCP server that issues different addresses and we don't
want to interfere with those ...

Thanks!
 
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