From: Kenneth Wygand (KWygand@customonline.com)
Date: Thu Oct 09 2003 - 12:37:30 GMT-3
Can you post the config of your 3550?
Thanks,
Kenneth E. Wygand
Systems Engineer, Project Services
CISSP #37102, CCNP, CCDP, MCP 2000, CNA 5.1, Network+, A+
Custom Computer Specialists, Inc.
"In order to understand how a router will handle a particular situation,
you first must 'be' the router."
-Anonymous
-----Original Message-----
From: Connie Nie [mailto:CNie@EPLUS.com]
Sent: Thursday, October 09, 2003 9:19 AM
To: ccielab@groupstudy.com
Subject: RE: OPSF big mess!!!
Notice that show interface on R2 does not have 139.10.87.0/24, so I
assume
it is an interface on 3550. If I remembered right, within the same area
of
OSPF, the router id will be the original advertising router, in this
case,
3550; and "via x.x.x.x" in the routing table is the next hop address.
Connie
-----Original Message-----
From: Hunt Lee [mailto:hunt_lee@bigpond.net.au]
Sent: Thursday, October 09, 2003 7:51 AM
To: ccielab@groupstudy.com
Subject: OPSF big mess!!!
Hello Group,
I have a very strange scenario.
I always configured the OSPF distance command by Router ID... but I got
stuck on this today.
R1 R2
| |
-------------------------------
|
3550
So they all connected to Ethernet.
Now on R1 routing table
O IA 139.10.45.0/24 [110/75] via 139.10.120.2, 00:00:12,
Ethernet0.120
O IA 139.10.52.0/24 [110/1572] via 139.10.120.2, 00:00:12,
Ethernet0.120
O IA 139.10.65.0/24 [110/138] via 139.10.120.2, 00:00:12,
Ethernet0.120
O E2 139.10.67.0/24 [110/20] via 139.10.120.2, 00:00:12,
Ethernet0.120
O E2 139.10.69.0/24 [110/20] via 139.10.120.2, 00:00:12,
Ethernet0.120
O E2 139.10.87.0/24 [110/20] via 139.10.120.2, 00:00:12,
Ethernet0.120
O E2 139.10.89.0/24 [110/20] via 139.10.120.2, 00:00:12,
Ethernet0.120
Say I wanted to change the distance of 139.10.87.0/24 from 110 to 130
Now. 139.10.120.2 is eth IP of R2, and R2's Router ID is 139.10.2.2 (as
below)
r2#sh ip int brief
Interface IP-Address OK? Method Status
Protocol
BRI0 139.10.52.2 YES NVRAM up
up
BRI0:1 unassigned YES unset down
down
BRI0:2 unassigned YES unset down
down
Ethernet0 139.10.120.2 YES NVRAM up
up
Loopback0 139.10.2.2 YES NVRAM up
up
Serial0 139.10.100.2 YES NVRAM up
up
Serial1 unassigned YES NVRAM administratively
down
down
Virtual-Access1 unassigned YES TFTP down
down
r2#sh ip ospf
Routing Process "ospf 1" with ID 139.10.2.2
Supports only single TOS(TOS0) routes
Supports opaque LSA
It is an area border router
Now R1(config)#access-list 5 permit 139.10.87.0 0.0.0.255
and
R1(config-router)#distance 130 139.10.2.2 0.0.0.0 5
R1#clear ip ospf process
Reset ALL OSPF processes? [no]: yes
R1#
Looking back into the routing table, nothing happened
O E2 139.10.20.0/24 [110/20] via 139.10.120.2, 00:00:18,
Ethernet0.120
O IA 139.10.45.0/24 [110/75] via 139.10.120.2, 00:00:18,
Ethernet0.120
O IA 139.10.52.0/24 [110/1572] via 139.10.120.2, 00:00:18,
Ethernet0.120
O IA 139.10.65.0/24 [110/138] via 139.10.120.2, 00:00:18,
Ethernet0.120
O E2 139.10.67.0/24 [110/20] via 139.10.120.2, 00:00:18,
Ethernet0.120
O E2 139.10.69.0/24 [110/20] via 139.10.120.2, 00:00:18,
Ethernet0.120
O E2 139.10.87.0/24 [110/20] via 139.10.120.2, 00:00:18,
Ethernet0.120
But when I look at that route closer
R1#sh ip route 139.10.87.0
Routing entry for 139.10.87.0/24
Known via "ospf 1", distance 110, metric 20, type extern 2, forward
metric
75
Redistributing via eigrp 100
Advertised by eigrp 100
Last update from 139.10.120.2 on via Ethernet0.120.120, 00:00:43 ago
Routing Descriptor Blocks:
* 139.10.120.2, from 139.10.10.1, 00:00:43 ago, via Ethernet0.120
Route metric is 20, traffic share count is 1
R1#
It said from "139.10.10.1", which is the IP of Loopback (router id) of
my
3550
Loopback0 139.10.10.1 YES manual up
up
Switch1#
Switch1#sh ip ospf
Routing Process "ospf 1" with ID 139.10.10.1
Supports only single TOS(TOS0) routes
Supports opaque LSA
And this time, i applied distance on that 3550's Router ID (139.10.10.1)
and
it work
So my question is, where is the main routing table telling me something
different?
And what is the * 139.10.120.2 from 139.10.120.10 mean?
* 139.10.120.2, from 139.10.120.10, 00:00:43 ago, via Ethernet0.120
Route metric is 20, traffic share count is 1
ANd should I just always just use the IP by the "from field" to work out
the
OSPF router ID, rather than the one from main routing table? (which is
what
I have been doing)
And I don't even understand why the router id would suddenly jump to
3550,
rather than R2!!!
Any help would be greatly appreciated.
Hunt
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