Cisco Nexus 6000 Series NX-OS Unicast Routing Command Reference
A Commands
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A Commands

Table Of Contents

A Commands

authentication (HSRP)

A Commands

This chapter describes the Cisco NX-OS Hot Standby Router Protocol (HSRP) commands that begin with A.

authentication (HSRP)

To configure authentication for the Hot Standby Router Protocol (HSRP), use the authentication command. To disable authentication, use the no form of this command.

authentication {string | md5 {key-chain key-chain | key-string {0 | 7} text [timeout seconds]} | text string}

no authentication {string | md5 {key-chain key-chain | key-string {0 | 7} text [timeout seconds]} | text string}

Syntax Description


Specifies the Message Digest 5 (MD5) authentication.

key-chain key-chain

Identifies a group of authentication keys.


Specifies the secret key for MD5 authentication.


Specifies a clear text string.


Specifies an encrypted string.


Secret key for MD5 authentication. The range is from 1 to 255 characters. We recommend that you use at least 16 characters.

timeout seconds

(Optional) Specifies the authentication timeout value. The range is from 0 to 32767.

text string

Specifies an authentication string. The range is from 1 to 255 characters. The default string is "cisco".

Command Default


Command Modes

HSRP configuration or HSRP template mode

Command History



This command was introduced.

Usage Guidelines

Use the authentication text command to prevent misconfigured routers from participating in HSRP groups that they are not intended to participate in. The authentication string is sent unencrypted in all HSRP messages. The same authentication string must be configured on all routers in the same group to ensure interoperation. HSRP protocol packets that do not authenticate are ignored.

Caution If you configure two routers with identical HSRP IP addresses but with different authentication strings, then neither router is aware of the duplication.


This example shows how to configure an authentication string for HSRP group 2:

switch# configure terminal
switch(config)# interface ethernet 0/1
switch(config-if)# no switchport
switch(config-if)# ip address
switch(config-if)# hsrp 2
switch(config-if-hsrp)# priority 110
switch(config-if-hsrp)# preempt
switch(config-if-hsrp)# authentication text sanjose
switch(config-if-hsrp)# ip
switch(config-if-hsrp)# end

Related Commands


feature hsrp

Enables HSRP and enters HSRP configuration mode.

hsrp group

Creates an HSRP group.