(PM) DHCP

MegaZone (megazone@livingston.com)
Wed, 4 Feb 1998 23:44:04 -0800 (PST)

Ok, all this DHCP stuff got me to stay late (arg, and I have to do another
training class in the morning) and I looked at the other customers I knew
of, what was being attempted here, and what we do. I was lucky enough to
catch one of the other engineers on it too.

Short answer - WE WILL NOT PROXY DHCP COMING IN FROM THE ETHERNET.

The way the proxy was implemented it was in response to server requests
we had to handle DHCP requests coming in over the external links. So
the code only handles proxy requests that come in over a Point-To-Point
interface.

Part of the misunderstanding is my fault. I worked with people using
PMs at remote sites handling DHCP over a WAN link back to a server. But
the clients making the requests were NOT on the ether, but on the serial
ports. When I saw the latest request in my mind's eye I mis-remembered
what had worked as what was being tried. Which is why I couldn't
understand why it wasn't working in this case.

Being able to handle proxy requests from the ethernet is a more complex
propisition. We talked about it and looked at the code, and to be safe
we need to do some kind of 'split-horizon'. So that we don't resend a
request out of the same interface we got it in on.

We'd have to get the request, determine which interface it came in on,
find our route to the proxy host, and then resend it only if the route
wasn't on the same interface. If it was the same we'd have to drop it.

None of that intelligence is there now, we just get it and pass it on
since a PTP link isn't a broadcast medium like ether, where it would be
likely to have a server on the ether in many cases.

So the answer is - I'm sorry, I half-remembered what was being done.
What you are trying to do with two units and proxying requests from the
ethernet will NOT work today. And it won't be a short term fix, so I
can't promise that it will be in 3.8. In fact, as 3.8 is well along,
most likely it will not be in that release.

But we are doing further DHCP work in relation to the NAT code, and we
may be able to tag this on to that project.

Sorry for the confusion and frustration.

-MZ

--
Lucent Remote Access Division - Chair, Department of Interstitial Affairs
Phone: 800-458-9966 510-737-2100 FAX: 510-737-2110 megazone@livingston.com
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