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masdf123
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Cisco 881 SSH access from outside

Hello,

We are using a Cisco 881 and would like to allow SSH to the router from outside (any source)

Currently we have a NAT inside and outside.

Please help with this. Router is running the latest firmware of 15.x I believe.

Thanks
RoutersHardware FirewallsCisco

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Jody Lemoine

8/22/2022 - Mon
Istvan Kalmar

Hi,


you need:

int loop 1
 ip add 1.1.1.1 255.255.255.25
 ip nat inside
ip nat inside source static tcp 1.1.1.1 22 x.x.x.x 22

where x.x.x.x the public ip of the router!

Best regards,
Istvan
Jody Lemoine

Once you enable SSH on the router, it it open from all sources by default. Outside access requires no further configuration unless you are using access lists or the zone based firewall to control traffic coming in from outside sources. If this is the case, you need to make sure that traffic to the router's public IP with destination port 22/tcp is permitted in the outside interface's access list (if you're just using access lists) or to the "self" zone (if you're using the zone based firewall.)
masdf123

ASKER
jodylemoine, Could you guide me with the SSH enabling lines as well.

Thanks
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Jody Lemoine

Sure.

From global configuration mode (conf t) do the following:

Set the hostname and domain names if you haven't already with:

hostname xxx
ip domain-name domain.com

Generate the encryption keys for ssh:

crypto key generate rsa modulus 2048

Set the default ssh version to 2.0:

ip ssh version 2

Write the configuration and you should be good to go.
masdf123

ASKER
And if there are ACLs on the outside interface, I should just allow port 22 in, correct?
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Jody Lemoine

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