From: Srikanth Nagarajan (nsrikanth@xxxxxxxxxxx)
Date: Thu Jun 17 1999 - 13:58:29 GMT-3
Hi Ben,
Iam trying to understand in your config for ospf, you have specified:
network 172.16.1.146 0.0.0.0 area 0
Normally, when you specify the networks onto which you want to run OSPF you
specify the network address and the mask so that all the networks n which
you want run ospf on are covered.
What is the significance of your specifying a host address 172.16.1.146 with
mask 0.0.0.0 ?
Pl clarify
Thanks in advance
Srikanth N
>From: "Robert Caamano" <rcaamano@rpm.com>
>Reply-To: "Robert Caamano" <rcaamano@rpm.com>
>To: "Ben Rife" <brife@bignet.net>
>CC: <ccielab@groupstudy.com>
>Subject: Re: OSPF and Loopback intf.
>Date: Wed, 16 Jun 1999 20:15:54 -0400
>
>Ben,
>
>The answer to your question is this:
>
>By default OSPF treats Loopback interfaces differently than a regular
>interface in that it
>considers it a stub host. You will notice that you have a route that has a
>/32 mask
>(172.16.1.161/32). This address is the primary Loopback address and the
>only Loopback address
>advertised by default. OSPF advertises it this way to identify that it is
>a
>stub host interface.
>
>Here's how you make it work
>
> type the following
>
>#conf t
>(config)#int lo0
>(config-if)#ip ospf netw point-to-point
>
>This will make ospf see the loopback interface as a point to point network
>instead of a stub host
>and will then allow normal rules for secondary interface advertizment
>apply.
>
>
>-----Original Message-----
>From: Ben Rife <brife@bignet.net>
>To: Rick Burts <burts@ccci.com>
>Cc: ccielab@groupstudy.com <ccielab@groupstudy.com>
>Date: Wednesday, June 16, 1999 11:50 AM
>Subject: Re: OSPF and Loopback intf.
>
>
> >I just can't get this to work. My secondary networks on the loopback on
> >r2520 will not show up in the route table of r2503. Here is my OSPF and
> >Loopback configs....
> >
> >Router 2503
> >
> >r2503#sh run
> >Building configuration...
> >
> >Current configuration:
> >!
> >version 11.2
> >no service password-encryption
> >no service udp-small-servers
> >no service tcp-small-servers
> >!
> >hostname r2503
> >!
> >!
> >no ip domain-lookup
> >isdn switch-type basic-ni1
> >!
> >interface Ethernet0
> > ip address 192.168.40.2 255.255.255.0
> >!
> >interface Serial0
> > ip address 172.16.1.146 255.255.255.240
> >!
> >interface Serial1
> > no ip address
> > clockrate 64000
> >!
> >interface BRI0
> > no ip address
> > isdn spid1 0835866101 8358661
> > isdn spid2 0835866301 8358663
> >!
> >router ospf 10
> > network 172.16.1.146 0.0.0.0 area 0
> >!
> >no ip classless
> >!
> >!
> >line con 0
> >line aux 0
> >line vty 0 4
> > login
> >!
> >end
> >
> >
> >
> >
> >Router 2520
> >
> >
> >r2520#sh run
> >Building configuration...
> >
> >Current configuration:
> >!
> >version 11.2
> >no service password-encryption
> >no service udp-small-servers
> >no service tcp-small-servers
> >!
> >hostname r2520
> >!
> >!
> >no ip domain-lookup
> >!
> >interface Loopback0
> > ip address 172.16.1.225 255.255.255.240 secondary
> > ip address 172.16.1.193 255.255.255.240 secondary
> > ip address 172.16.1.129 255.255.255.240 secondary
> > ip address 172.16.1.161 255.255.255.240
> >!
> >interface Ethernet0
> > no ip address
> >!
> >interface Serial0
> > no ip address
> > shutdown
> > no fair-queue
> >!
> >interface Serial1
> > no ip address
> > shutdown
> > clockrate 56000
> >!
> >interface Serial2
> > ip address 172.16.1.145 255.255.255.240
> > bandwidth 1544
> > clockrate 56000
> >!
> >interface Serial3
> > no ip address
> > shutdown
> >!
> >interface BRI0
> > no ip address
> > shutdown
> >!
> >router ospf 10
> > network 172.16.1.161 0.0.0.0 area 0
> > network 172.16.1.225 0.0.0.0 area 0
> > network 172.16.1.129 0.0.0.0 area 0
> > network 172.16.1.193 0.0.0.0 area 0
> > network 172.16.1.145 0.0.0.0 area 0
> >!
> >no ip classless
> >lat service ABLE password CISCO
> >!
> >!
> >line con 0
> >line aux 0
> >line vty 0 4
> > login
> >!
> >end
> >
> >
> >
> >
> >Route table of r2503
> >
> >r2503#sh ip route
> >Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
> > D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
> > N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
> > E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
> > i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate
> >default
> > U - per-user static route, o - ODR
> >
> >Gateway of last resort is not set
> >
> >C 192.168.40.0/24 is directly connected, Ethernet0
> > 172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks
> >O 172.16.1.161/32 [110/65] via 172.16.1.145, 00:05:15, Serial0
> >C 172.16.1.144/28 is directly connected, Serial0
> >
> >
> >
> >Thanks for any help you can provide,
> >
> >Ben Rife
> >CCIE Candidate
> >
> >
> >
>
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