My initial reaction to this was pretty much the same asTom's: surmising that AT&T had adopted the widespread ISP practice of running its DHCP servers on private addresses. This has several advantages for them, not *just* address conservation. One is that hosts who fail authentication tests (e.g., MAC address checking) can be assigned private-range addresses ... not routable, but able to connect to an AT&T Web server for troubleshooting, MAC-address updating, whatever is needed ... it's a timesaver (for the ISP, not the customer, as usual) I'm seeing reported more and more often.

I would be confident about this interpretation, except for two things you say:

(3) If I setup on a single PC as DHCP and bypass the
LRP box, I get the correct ATT DHCP server, DNS info
etc.
... and ...
AT&T as usual has no clue, so I replaced the modem but
get the same results.
If AT&T had switched to using a 10.b.c.d address for its DHCP server, presumably someone at AT&T would know about it. So you might want to consider what actual interaction with AT&T you based this assessment on. Was it just an uninformed tech-support person giving you the brush-off, or did someone competent actually investigate your concern and say they knew nothing about the DHCP server?

Oh, one final thing ... if your firewall package (whichever one you are using with Dachstein; you don't appear to say) is blocking all traffic from this private address, you will eventually have problems renewing your DHCP lease from that server (the other DHCP server may be present just to handle that eventuality, though ... that would be a smart thing for AT&T to do). If this is a problem, you'll need to modify your ipchains rulesets to allow traffic between (to and from) that server's port 67 and your router's eth0.

At 01:25 PM 11/24/02 -0800, Ivory Williams wrote:
Iam using Dacstein 1.0.2 with all defaults. Dual
floppy's [write protected] (only configured both
NIC's) for over a year with no problems on an ATT
cable modem network.

The system is LRP on 486 using default 192.168.1.254
2 ISA NIC's
 LRP NIC #1 (eth0) to Motorola Cable Modem
 LRP NIC #2 (eth1) to Addtron Router Cable Port
(crossover cable)
Addtron E200P hardware router (192.168.2.1)
ATT Motorol Surfboard cable modem
Various internal PC's connect to Router at 192.168.2.x
(statc ip's)

Normally it picks up my ATT DHCP server at 24.126.x.x
and returns a DHCP IP of 24.x.x.x. which usually
doesn't change for 90 days or more.

Problem:
What is now happening is the DHCP Offer is from a
10.235.112.1 (a privite IP address) as a  DHCP server
but returns the same IP address I usually receive from
the ATT DHCP server (24.x.x.x).
[details deleted]

--
-------------------------------------------"Never tell me the odds!"--------
Ray Olszewski					-- Han Solo
Palo Alto, California, USA			  [EMAIL PROTECTED]
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