SSH: internal working but external not working

UNIX Solaris
1

Hi, This is a strange issue: We have an sftp server. Users can ssh to it from internal LAN without any issue, but they can not ssh to it externally via firewall. Here is what I got:

OS is Solaris 9. No hosts.allow and hosts.deny files.

Please help. Thank you in advance!

2

If it gets that far it certainly doesn't seem like a firewall issue... Could it be a problem with PAM?

3

Yes. It gets as far as to the logon prompt.

What PAM issue can be to make internal work, but external not work?

Thanks.

4

As Corona668 says, the difference is that there's a firewall (and possibly a router?) in the way. From the external client what happens exactly?

It the router config set up correctly on the ssh server? Does this machine know how to return the call?

If you get the ip address of the external client which can't connect, what happens if you try to ping that address from the ssh server?

5

I didn't think it was a firewall problem. It'd take a very strange kind of dynamic firewall to allow them to connect and communicate but not allow them to authenticate.

I'm not precisely sure what PAM trouble could cause this. PAM doesn't usually differentiate between different network locations itself. But I understand some systems had implemented PAM add-ons to do so. Maybe just glance in your PAM configuration and see if you find anything related. (But don't touch it lightly, either. Messing up PAM may require a rescue CD to recover from.)

6

I've added the following line into /etc/ssh2/sshd2_config and restarted sshd:

Still not working. The system is in DMZ. I may need to find out if ssh is disabled by DMZ. Any idea?

7

edit the ssh config file

i adde below entry
sshd : ALL
save and exit

8

I gave up. SSH under Solaris 8/9 is just not stable and mature. Instead of troubleshooting the issue, I've built a new SFTP server using SuSE Linux. External SSH works well right after the configuration is done.

Thank you again!