[c-nsp] Strange IP on PPPoE interface

[Artyom Viklenko]

Hi, All!

  Occasionally, I've got faced with strange situation.
We have several Cisco 28xx acting as a PPPoE access concentrators.
One of them - cisco 2801 - was dedicated for cheap tariff plans and
assign IP addresses for customers from local pool but authorize them
via RADIUS.

At some point of time I found, that one customer have wrong IP
on it's Virtual-Access interface:

# sh users
...
Vi22         username             PPPoE        00:04:26 0.4.0.0
...

As I found later, this was caused by customer's router D-Link DIR-100
Dial-On-Demand feature. But I can't figure out why Cisco accepted
peer's ip-address.

Some portions of config:


!
bba-group pppoe CHEAP
  virtual-template 1
  sessions per-mac limit 1
  sessions per-mac throttle 1 5 5
!
interface Virtual-Template1
  ip unnumbered FastEthernet0/0.349
  no ip redirects
  no ip proxy-arp
  ip route-cache flow
  ip tcp adjust-mss 1452
  autodetect encapsulation ppp
  peer ip address forced
  peer default ip address pool CHEAP-1
  keepalive 10 6
  ppp authentication chap pap
  ppp ipcp dns x.x.x.x y.y.y.y
  ppp ipcp address required
  ppp ipcp address unique
!
ip local pool CHEAP-1 z.z.z.1 z.z.z.254
!


As I understnad Ciscos docs, router should
NAK peer's IP and negotiate it from local
pool.

IOS in question is:

Cisco IOS Software, 2801 Software (C2801-ADVENTERPRISEK9-M), Version 
12.4(23), RELEASE SOFTWARE (fc1)


Does anybody can point me in right direction, please?
Is it an IOS bug, or I misundersood something?

Thanks in advance!



-- 
            Sincerely yours,
                             Artyom Viklenko.
-------------------------------------------------------
artem at aws-net.org.ua | http://www.aws-net.org.ua/~artem
artem at viklenko.net   | ================================
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