Alcatel OmniSwitch 6624 Troubleshooting Manual page 181

Troubleshooting IP Routing
domainName :
nameServer(s):
Verify that the switch has a valid route to the destination subnet via the show ip route command:
-> show ip route
Dest Address
------------------+-----------------+-----------------+---------+-----------
127.0.0.1
192.168.1.0
192.168.10.0
192.168.10.1
If a route is listed to the destination's network, you should be able to ping it. If this ping fails, you will
need to determine why. Verify RIP, OSPF, or BGP configurations so that the unit can learn the proper
route to the destination.
The show ip protocols command will tell you what routing protocols are loaded, giving you a starting
point for investigation.
-> show ip protocols
Router ID
Primary addr
RIP status
OSPF status
BGP status
DVMRP status
PIMSM status
Debug level
Debug sections
A traceroute command (tracert in Windows, traceroute from a UNIX/Linux machine, and from the
Falcon CLI) should indicate where the path has failed. If it fails on an intermediate hop between the
Falcon and the destination, your efforts should be expended on the device that showed a failure in the
path. Note that this may lead you back to another device to troubleshoot some other sort of failure, such as
link down, etc. If the traceroute ends at the gateway to the destination VLAN, you do not have a routing
problem, but rather a likely problem in the destination VLAN with either physical issues (cabling, bad
NICs, dropped packets, etc.), Source Learning, or device IP setup.
-> traceroute 192.168.1.2
traceroute to 192.168.1.2, 30 hops max, 40 byte packets
192.168.1.2 50 ms
The show icmp statistics command may help by giving you an indication of redirect messages being sent.
These usually indicate that the route in question has an issue, and that the router instance knows of a
different route to get to the destination. From there you can look at the show ip route command to see
what your routing table looks like. Verify via this command that the routes you think a packet should take
are properly displayed in the table, and contrast that with any differences noted by the traceroute
command output.
-> show icmp statistics
Messages
---------------------------+----------+-------------
Total
Error
OmniSwitch Troubleshooting Guide
Subnet Mask Gateway Addr
255.255.255.255
255.255.255.0
255.255.255.0
255.255.255.255
33.3333 ms 33.3333 ms
Received
9579
0
September 2005
Age
127.0.0.1 00:14:39
192.168.1.1 00:13:08
192.168.10.50 00:14:35
192.168.11.1 00:14:35
= 192.168.1.1,
= 192.168.1.1,
= Not Loaded,
= Not Loaded,
= Not Loaded,
= Not Loaded,
= Not Loaded,
= 1,
= none
Sent
9392
15
Troubleshooting via the CLI
Protocol
LOCAL
LOCAL
LOCAL
NETMGT
page 12-5