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Can not SSH to the public IP provided by Comcast

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Last Modified: 2020-07-17
Third time was a charm - sort of - with Comcast. The first two cable modems my Cisco ISR 1111 could not get a mac address
from Comcast. The third tech came out today. And with no change in configuration on my router I was able to ping the public
IP of the router and all devices of the site would reach the Internet.

The problem: I can not SSH to the outside interface of the router. And the router is refusing to form a tunnel as a spoke of
a DMVPN mesh. While the tech was there and for a while - I could ssh to the router's outside interface. But in the shuffle
he rebooted and left before I could vet everything from remote. The router came up but this time there was no way to
ssh to it. No changes had been made to the router. I'm just stumped. The router should be in bridged mode I think.
Anyone run into an issue like this wish comcast?
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some oneNetwork Architect
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Top Expert 2014

Commented:
Is the router outside IP a public or private one?
David FavorFractional CTO
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Distinguished Expert 2019

Commented:
There are 2x requirements.

1) SSH port you're using must be open on source + target machines (and all machines in between). Default port == 22.

2) There must be an sshd daemon running on the target machine.

These are the 2x places for you to debug.

Provide the ssh command you're using, along with full error output, for best comments.
amigan_99Network Engineer

Author

Commented:
The router's external IP address is a public IP.

The router permits SSH traffic to the public interface and VTY 0 ACL permits the traffic from the source IP from which I was operating. And we know it is working because for a time while the tech was onsite and while the router was pingable, I was able to SSH to the outside public IP address. Likewise this indicates that ssh daemon is running. Another reason we know SSH daemon is running is that if I Zoho to a desktop at the remote site, on the inside of the router, there is no problem SSHing to the inside interface of the router.

I am running putty to try and ssh to the router. Perhaps there is some debug I could run with it?
some oneNetwork Architect
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Top Expert 2014

Commented:
Can you post the config for the router, please? Omit any sensitive data such as usernames and passwords.
amigan_99Network Engineer

Author

Commented:
Have a look. If you see anything wonky for SSH or the tunnel turn up I'm all ears. The certificate for the tunnel is missing as the cert pull is failing for reasons unknown.
Cleaned-Config.txt
some oneNetwork Architect
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Top Expert 2014

Commented:
Do...

no ip ssh source-interface Loopback0

...and see if you can get in then.
amigan_99Network Engineer

Author

Commented:
ip ssh source-interface command defines the source IP when starting an SSH session from the router. ?
some oneNetwork Architect
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Top Expert 2014

Commented:
Yes. I just want to make sure NAT or your route-map isn't doing anything funny with it.

Saying that, I've put your config on a router in my lab and it doesn't play nice with the line config you have. If I take away the authorization and authentication from the line I can SSH to the router with no issue.

Temporarily try:
aaa authentication login default local
aaa authorization exec default local
line vty 0 15
 no authorization exec SECURE
 no login authentication SECURE

amigan_99Network Engineer

Author

Commented:
Well I know that I was able to SSH to the outside interface at one point in the circuit turnup. And that included getting the login prompt and using the local credentials to gain access. So I'm certain the VTY config is ok for access. In the worst case it that was goofed up it would prevent me from authenticating. But SSH being enabled should make port 22 visible to a port scanner at the very least. And it's not.
some oneNetwork Architect
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Top Expert 2014

Commented:
OK remove the ACL and see if you get a response. 
Network Engineer
Commented:
This one is on us!
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