User Manual
UMN:CLI
V8102
709
12.4.12
Split Horizon
Normally, routers that are connected to broadcast type IP networks and that use distance-
vector routing protocols employ the split horizon mechanism to reduce the possibility of
routing loops. Split horizon blocks information about routes from being advertised by a
router out any interface from which that information originated. This behavior usually op-
timizes communications among multiple routers, particularly when links are broken. How-
ever, with non-broadcast networks, such as Frame Relay, situations can arise for which
this behavior is less than ideal. For these situations, you might want to disable split hori-
zon.
If the interface is configured with secondary IP address and split horizon is enabled, up-
dates might not be sourced by every secondary address. One routing update is sourced
per network number unless split horizon is disabled.
To enable or disable split horizon mechanism, use the following command in
Interface
Configuration
mode.
Command
Mode
Description
ip rip split-horizon
[
poisoned
]
Interface
[VLAN]
Enables the split horizon mechanism.
poisoned: performs poisoned reverse.
no rip ip split-horizon
[
poisoned
]
Disables the split horizon mechanism.
12.4.13
Authentication Key
RIP v1 does not support authentication. If you are sending and receiving RIP v2 packets,
you can enable RIP authentication on an interface. The key chain determines the set of
keys that can be used on the interface. If a key chain is not configured, plain text authen-
tication can be performed using string command.
The V8102 supports two modes of authentication on an interface for which RIP authenti-
cation is enabled: plain text authentication and MD5 authentication. The default authenti-
cation in every RIP v2 packet is plain text authentication.
Do not use plain text authentication in RIP packets for security purposes, because the
unencrypted authentication key is sent in every RIP v2 packet. Use plain text
authentication when security is not an issue, for example, to ensure that misconfigured
hosts do not participate in routing.
To use RIP protocol, you should enable RIP.
Step 1
To create a name for key chain for the management, use the following command on
Global Configuration
mode.
Command
Mode
Description
key chain WORD
Global
Creates a name for the key chain
no key chain WORD
Deletes a name for the key chain
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