PPP get 2 ips

[Guy Silliman]

I am running pppd version 2.3 patch level 5, set up for pppoe to 
maintain a DSL connection.

My Config is working great, but here it is any - missing the sensative stuff
#
# ppp.conf: PPPoE Configuration
#
default:
 # PPP over Ethernet
 set device PPPoE:dc1
 set speed sync
 set mru 1492
 set mtu 1492
 set ctsrts off
 # monitor line quality
 enable lqr
 # log just a bit
 set log phase tun
 # insert default route upon connection
 add default HISADDR
 # download /etc/resolv.conf
 enable dns
 # enable nat
 nat enable yes
 papchap:
 #
 # edit the next three lines and replace the items in caps with
 # the values which have been assigned by your ISP.
 #
 set authname *******************
 set authkey *********

I have had several occassions to find that the interface attached to the 
DSL connection is assigned 2 IP's.  The connection still works for me 
from the inside, and I can traffic data without a problem.  However, 
requests from the outside world fail.  I do run a mail server and web 
server off this connection, so incoming connections are kinda important.

I can't find anything in the logs to hint towards a problem.  Most 
times, I don't even know it has happened until I hear from a friend or 
relative who depends on it.

Any thoughts?