Troubleshooting Guide

3. INCOMPLETE neighbor state indicates a problem if the corresponding neighbor is used by
some of the IPv6 routes. This applies to neighbor entries with link-local addresses.
Note:
Global addresses are not normally used as next hops. Having a global IPv6 neighbor
entry as INCOMPLETE does not usually lead to a connectivity issue.
4. If the corresponding route is not in place then this is a routing issue. If the neighbor is not
present or is INCOMPLETE, then further debugging is needed on the network level (that is,
the state of other nodes needs to be examined).
5. Disabling and re-enabling IPv6 on the VLAN often recovers connectivity.
6. Display the RSMLT and MLT status:
show ip rsmlt
show mlt
Make sure the RSMLT peer MAC is learned and the IST state is ist.
Troubleshooting TACACS+
The switch supports the Terminal Access Controller Access Control System plus (TACACS+) client.
TACACS+ is a remote authentication protocol that provides centralized validation of users who
attempt to gain access to a router or network access server (NAS). The TACACS+ feature is
disabled by default.
The current implementation of TACACS+ does not support:
• Earlier versions of TACACS
• Point-to-Point Protocol (PPP) authentication and accounting
• IPv6 addresses
TACACS+ is part of the Base Software License. For more information about licensing, see
Administration for Avaya Virtual Services Platform 4000 Series, NN46251-600.
See the following sections to troubleshoot TACACS+.
Unable to log on using Telnet or rlogin
If you cannot log on using Telnet or rlogin, perform the following steps.
Procedure
1. Check whether the TACACS+ server is available or unreachable.
2. On the TACACS+ server, check whether you configured the privilege level correctly. On
successful authorization, the TACACS+ server returns an access level to the switch for the
Upper layer troubleshooting
January 2017 Troubleshooting 236
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