3Com Switch 8800 Configuration Guide Chapter 20 Integrated IS-IS Configuration
20-18
By default, the number of the invalid Hello packets is set to 3.
If this command does not specify Level-1 or Level-2, the system regard the invalid Hello
packets are set for both Level-1 and Level-2 routers.
20.2.16 Setting IS-IS Authentication

I. Setting interface authentication

The authentication password set on the interface is mainly used in the Hello packet so
as to confirm the validity and correctness of its peers. The authentication passwords at
the same level of all the interfaces of a network should be identical.
Perform the following configuration in interface view.
Table 20-21 Set interface authentication password
Operation Command
Set authentication password isis authentication-mode { simple | md5 }
password [ { level-1 | level-2 } [ ip | osi ] ]
Delete authentication-mode
password
undo isis authentication-mode { simple | md5 }
password [ { level-1 | level-2 } [ ip | osi ] ]
By default, the interface is not configured with any authentication password nor
performs authentication. If the level is not specified, it defaults to setting the
authentication password of Level-1.

II. Setting IS-IS area or IS-IS routing domain authentication password

Users can configure the IS-IS area or the IS-IS routing domain with authentication
password.
If area authentication is needed, the area authentication password will be encapsulated
into the level-1 LSP, CSNP and PSNP packets, in the specified mode. If other routers in
the same area also have started the area authentication, their authentication modes
and passwords must be identical to those of their neighbors, so that they can work
normally. Similarly, for domain authentication, the password will also be encapsulated
into the level-2 LSP, CSNP and PSNP packets in the specified mode. If the routers in
the backbone layer (level-2) also need domain authentication, their authentication
mode and password must be identical to those of their neighbors.
Note that the passwords for authentication of the routers on the same network segment
must be identical.
Perform the following configurations in IS-IS view.