Cisco - SSH Key Auth

Security
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Intro

do you wanna login into your cisco switches with ssh & public key. you can build your config easily and copy/paste it to your switch(es).

Set & Check Variables

  • pubkey: read from ~/.ssh/id_rsa.pub
  • username: root
  • password: will be generated. or set it by hand
# get & convert public key
pubkey=$(cat ~/.ssh/id_rsa.pub |cut -d' ' -f 2 |fold -b -w 72)

# Username Switch
username=root

# Password for User
password=$(openssl rand -hex 12)

# Full Line
echo "username $username privilege 15 password $password"

SSH Pubkey Auth Config Snippet

# Build Config
cat  << EOF


############################################
# Copy/Paste to your Cisco Devices - START #
############################################

conf t

# Set Version
ip ssh version 2
no aaa new-model

# Set User
username $username privilege 15 password $password

# Set Key
ip ssh pubkey-chain 
username $username 
key-string
$pubkey
exit
exit
exit

# vty Stuff
line vty 0 15
 login local
 transport input ssh

end
write
exit

############################################
# Copy/Paste to your Cisco Devices - END   #
############################################


EOF

you should test it in a lab environment before running on productiv switches ;)

Any Comments ?

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