question about the command "ip unnumberd loopback0"

[hondkaustralia]

Hello there!

Could you share your experience with me?

When I access to RAS from my PC through dialup connection, I get ip addresses of my ppp interface and nexthop.

I wanted to know how the process was going on in the RAS. So I checked the configuration on the cisco web site.

interface loopback 0

ip address 192.168.1.1 255.255.255.0

interface async1

ip unnumbered loopback 0

peer default ip address pool asyncpool

........

........

router eigrp 100

network 192.168.1.0 0.0.0.255

network 10.1.0.0 0.0.255.255

.........

........

ip local pool asyncpool 192.168.1.2 192.168.1.254

From the above, the RAS is configured for both async interface on RAS side and loopback interface to be assigned the same ip address as well as the two networks (async ppp and loopback) belong to the same ip network subnet.

What's happening in the routing table of the RAS? How can the two different interfaces have the same ip address?

I don't have any RAS. I can't check them out. Please help me with some advice.

[zubairjalal]

Check this link about understanding and configuring the ip unumbered command

http://www.cisco.com/warp/public/701/20.html

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[hondkaustralia]

Thanks for your input!

Could you help me one more?

When the command "peer defaul ip address pool ciscopool" is configured on an async interface of RAS, which protocol is actually resposible for delivering an ip address to a client PC?

I guess it could be ppp because there is no alternative. If it is ppp, which field of ppp packet is for the delivery function? I've never heard of this function in ppp.

Thanks!