[cisco-nas] Dialup Routing Q

[Michael Taylor (mitaylor)]

hi,

You might want to investigate classless routing (command: 'ip classless')

A description is here:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios113ed/113ed_cr/np1_c/1cipadr.htm#xtocid212805

 From what you are describing, you probably have 'ip classless' configured...

OR, you could add extra static routes with an admin distance for each 
specific subnet.

e.g.
ip route 172.16.1.0 255.255.255.0 Null0 240
ip route 172.16.2.0 255.255.255.0 Null0 240
ip route 172.16.3.0 255.255.255.0 Null0 240

Hope this helps,
Cheers,
Mike Taylor

At 10:22 PM Sunday 6/07/2003 -0500, Voralt wrote:
>I have a dialup routing question.
>
>Say I have several users dialing in via ISDN.  They each have a class C from
>the 172.16.x.x block and on the main site router I have the following
>routes:
>
>ip route 172.16.1.0 255.255.255.0 172.16.1.1
>ip route 172.16.2.0 255.255.255.0 172.16.2.1
>ip route 172.16.3.0 255.255.255.0 172.16.3.1
>ip route 0.0.0.0 0.0.0.0 1.1.1.1
>
>
>Each remote router is either 1.1, 2.1 or 3.1.  The users dialin ok and
>everything works fine, but if they are not connected, I am wondering what
>happens to data destined for their network.  So if the ISDN user at 1.1 is
>not dialed in, the static route is still there, but it appears that the data
>is sent out the default route, which then sends it back in and the TTL
>eventually expires.  I also have a summary static set to NULL0, which I
>would think would drop the traffic, but that doesn't appear to be the case.
>
>ip route 172.16.0.0 255.255.0.0 NULL0 240
>
>Can anybody explain exactly what's happening?  To summarize one more time, a
>central router has all of the routes listed above.  Traffic is sent to
>172.16.1.1, but that router is not dialed in at the moment, so what happens
>to traffic destined for that network?
>
>Thanks in advance.
>
>Peder
>
>_______________________________________________
>cisco-nas mailing list
>cisco-nas at puck.nether.net
>http://puck.nether.net/mailman/listinfo/cisco-nas

Cisco Systems,
Customer Support Engineer,
Asia Pacific Technical Assistance Centre,
Sydney, Australia
Ph:     (+61 2) 8446 6044