Troubleshooting guide

BSR Troubleshooting Guide
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7. If you altered an access list, enable the list to see whether the application can
still operate normally.
8. If the application operates normally, repeat the previous steps to isolate any
other problem access lists until the application operates correctly with all
access lists enabled.
Handling UDP Broadcast Forwarding Problems
The User Datagram Protocol (UDP) describes how messages reach application
programs within a destination computer. The following sections describe how to
solve problems that occur when forwarding BOOTP or other UDP broadcast
packets. For example, if UDP broadcasts sent from network hosts are not
forwarded by routers, or diskless workstations cannot boot.
• Missing or Misconfigured IP Helper-address Specification
• UDP Broadcast Misconfiguration
Missing or Misconfigured IP Helper-address Specification
1. Use the debug ip udp command in Privileged EXEC mode on the BSR that
should be receiving packets from the host. Check the output of the command
to see whether the BSR is receiving packets from the host.
2. If the router receives packets from the host, there is a problem with the host or
the application. Consult the host or application documentation.
3. If the router does not receive packets from the host, use the show
running-config command in Privileged EXEC mode to check the
configuration of the router interface that should first receive the packet from
the host.
Caution: The debug ip udp command can use considerable CPU
resources on the BSR. Do not execute the command if the network is
heavily congested. If the network is congested, attach a protocol analyzer
to see whether the BSR is receiving UDP broadcasts from the host.