04-09-2009 06:03 AM - edited 03-04-2019 04:18 AM
Question:
I'm trying to troubleshoot an issue with equal cost static default routes. Here is the configuration of the 3560:
..
interface FastEthernet0/1
no switchport
ip address 8.8.8.1 255.255.255.0
!
interface FastEthernet0/2
no switchport
ip address 9.9.9.1 255.255.255.0
!
interface Vlan1
ip address 50.50.50.1 255.255.255.0
!
....
!
ip route 0.0.0.0 0.0.0.0 8.8.8.2
ip route 0.0.0.0 0.0.0.0 9.9.9.2
"show ip route" output
Gateway of last resort is 9.9.9.2 to network 0.0.0.0
50.0.0.0/24 is subnetted, 1 subnets
C 50.50.50.0 is directly connected, Vlan1
8.0.0.0/24 is subnetted, 1 subnets
C 8.8.8.0 is directly connected, FastEthernet0/1
9.0.0.0/24 is subnetted, 1 subnets
C 9.9.9.0 is directly connected, FastEthernet0/2
S* 0.0.0.0/0 [1/0] via 9.9.9.2
[1/0] via 8.8.8.2
I'm pinging 4 different IPs out in the cloud with two equal cost default routes configured on a 3560. The IPs that I'm trying to ping are 1.1.1.1, 2.2.2.2, 3.3.3.3, and 4.4.4.4 - sourcing from 50.50.50.50. However, when I ping all four IP simutaneously it only egresses the 8.8.8.0 gateway.
I've used the "show ip cef exact-route" output. Which looks like it should distribute the load based on destination.
Switch#sh ip cef exact-route 50.50.50.1 1.1.1.1
50.50.50.1 -> 1.1.1.1 => IP adj out of FastEthernet0/1, addr 8.8.8.2
Switch#sh ip cef exact-route 50.50.50.1 2.2.2.2
50.50.50.1 -> 2.2.2.2 => IP adj out of FastEthernet0/1, addr 8.8.8.2
Switch#sh ip cef exact-route 50.50.50.1 3.3.3.3
50.50.50.1 -> 3.3.3.3 => IP adj out of FastEthernet0/2, addr 9.9.9.2
Switch#sh ip cef exact-route 50.50.50.1 4.4.4.4
50.50.50.1 -> 4.4.4.4 => IP adj out of FastEthernet0/1, addr 8.8.8.2
"show ip cef" output
Switch#sh ip cef
Prefix Next Hop Interface
0.0.0.0/0 8.8.8.2 FastEthernet0/1
9.9.9.2 FastEthernet0/2
"traceroute" output
Tracing the route to 1.1.1.1
1 8.8.8.2 0 msec
9.9.9.2 0 msec
8.8.8.2 0 msec
Any thoughts to why it only goes out one gateway and not both based on the cef table?
04-09-2009 07:12 AM
Denny,
Your equal cost static routing is working but the result is not showing as expected since you are doing it from the switch itself.
Best to setup a couple of clients in Vlan1 targeting different destinations to see the full effect.
__
Edison.
04-09-2009 07:17 AM
I've tried this from several different hosts connected to the switch with the same results.
04-09-2009 08:14 AM
From the traceroute you've shown, it's displaying the load-balancing taking effect.
__
Edison.
04-09-2009 08:40 AM
Yeah. That was the output from the switch and how packets should be traversing to the respective destinations. Testing is a different story altogether. Once I have multiple hosts connected to the switch each simultaneously pinging all the hosts mentioned - all traffic leaves one interface.
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