<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=Content-Type content="text/html; charset=us-ascii">
<META content="MSHTML 6.00.2900.3243" name=GENERATOR></HEAD>
<BODY>
<DIV><FONT face=Arial size=2><SPAN class=055075506-07032008>Hi
There,</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=055075506-07032008></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=055075506-07032008>Just wondering if
there's a way to stop this sort of routing loop from
happening.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=055075506-07032008></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=055075506-07032008>Say for example we
have a customer who has a PPP connection and when they login they get an IP
of 192.168.1.1.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=055075506-07032008>They now want an
additional /29 subnet and so through Radius we assign then a /29 (eg:
192.168.2.0/29).</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=055075506-07032008></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=055075506-07032008>Internet -> ISP
(LNS) -> Cust Route (PPP) -> Cust additional /29
subnet</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=055075506-07032008></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=055075506-07032008>
<DIV><FONT face=Arial size=2><SPAN class=055075506-07032008>I gather the static
route for this additional /29 subnet is injected to the router from Radius
becauses there's no hard set "ip route" command on the LNS and OSPF then
restributes this static route using the command "redistribute static
subnets" as seen in the "sh ip route" command below.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=055075506-07032008></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=055075506-07032008>lns#sh ip route
192.168.2.0<BR>Routing entry for 192.168.2.0/29</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=055075506-07032008> Known via
"static", distance 1, metric 0<BR> Redistributing via ospf 100<BR>
Advertised by ospf 100 subnets<BR> Routing Descriptor Blocks:<BR>
* 192.168.1.1<BR> Route metric is 0, traffic
share count is 1<BR></DIV></SPAN></FONT></SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=055075506-07032008><FONT face=Arial
size=2><SPAN class=055075506-07032008>My problem is that if the
customer doesn't use the additional /29 subnet and traffic is destined for
the additional /29 subnet we get a routing loop happening because the customer's
router sends the packet out it's default route back to the ISP's LNS and
then the ISP's LNS thinking it has a static route sends it back to the
customer's router and round and round we go til the TTL expires.
</SPAN></FONT></SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=055075506-07032008><FONT face=Arial
size=2><SPAN class=055075506-07032008></SPAN></FONT></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=055075506-07032008><FONT face=Arial
size=2><SPAN class=055075506-07032008>Can this routing loop be stopped from
the ISP (LNS) side??? Note that we are using OSPF on our network with the
following config below and the static route mentioned above I assume is injected
from Radius because there's no hard set "ip route" command for that additional
/29 subnet on the LNS.</SPAN></FONT></SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=055075506-07032008><FONT face=Arial
size=2><SPAN class=055075506-07032008></SPAN></FONT></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=055075506-07032008><FONT face=Arial
size=2><SPAN class=055075506-07032008>router ospf 100<BR> router-id
203.17.x.x<BR> log-adjacency-changes<BR> redistribute connected
subnets<BR> redistribute static subnets<BR> network 203.10.x.x 0.0.0.0
area 0<BR></SPAN></FONT></SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=055075506-07032008>Thankyou in
advance.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>--</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Regards,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Andy</FONT></DIV></BODY><!--[object_id=#staff.netspace.net.au#]--><P align=left><FONT face=Arial size=1>This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. Please notify the sender immediately by email if you have received this email by mistake and delete this email from your system. Please note that any views or opinions presented in this email are solely those of the author and do not necessarily represent those of the organisation. Finally, the recipient should check this email and any attachments for the presence of viruses. The organisation accepts no liability for any damage caused by any virus transmitted by this email.</FONT></P></HTML>