Cdp Problems - HP ProCurve 6400cl Series Management And Configuration Manual

Troubleshooting
Unusual Network Activity
C-12
To avoid inadvertently blocking the remote gateway for authorized traffic
from another network (such as the 20 Net in this example):
1. Configure an ACE that specifically permits authorized traffic from the
remote network.
2. Configure narrowly defined ACEs to block unwanted IP traffic that would
otherwise use the gateway. Such ACEs might deny traffic for a particular
application, particular hosts, or an entire subnet.
3. Configure a "permit any" ACE to specifically allow any IP traffic to move
through the gateway.
Local Gateway Case. If you use the switch as a gateway for traffic you want
routed between subnets, use these general steps to avoid blocking the gateway
for authorized applications:
1. Configure gateway security first for routing with specific permit and deny
statements.
2. Permit authorized traffic.
3. Deny any unauthorized traffic that you have not already denied in step 1.

CDP Problems

A Series 5300xl switch does not appear in the CDP Neighbors table of
an adjacent CDP Device. This may be due to any of the following:
■ Either the port connecting the switch to the adjacent device is not a
member of an untagged VLAN or any Untagged VLAN to which the
port belongs does not have an IP address.
■ If there is more than one physical path between the switch and the
other CDP device and STP is running on the switch, then STP will
block the redundant link(s). In this case, the switch port on the
remaining open link may not be a member of an untagged VLAN, or
any untagged VLANs to which the port belongs may not have an IP
address.
■ The adjacent device's CDP Neighbors table may be full. Refer to the
documentation provided for the adjacent CDP device to determine
the table's capacity, and then view the device's Neighbors table to
determine whether it is full.