I have a server running Red Hat Enterprises ES 3.0 and it works great. The problem I'm having is that I cannot logon to the server from a remote site using ssh. I have a Linksys WRT54GS router connected to a cable modem. I have set up port forwarding, etc on the router, disabled dhcp as well as the firewall. I use Anzio terminal emulator at the remote site but I continue to get this error when trying to connect.... "Could not open connection to the host, on port 23 (when using telnet): cannect failed.." The router is set to forward port 23 or 22 to the Linux server that has a static ip of 192.168.1.100). The router is using a static ip address from the ISP.

On the same server I have a second thernet card and a DSL connection to that card. No router and I am able to connect using telnet or ssh. Am I missing something in the setup of the router or something else?

Any help would be appreciated.


William Knowles
Nassau, Bahamas

You need to open port 22 on the Linux firewall (don't allow remote telnet traffic, it's a security issue).

Original post says firewall disabled. Maybe only for one of eth0, eth1 if two interfaces present?

For further diagnosis, running

# tcpdump port 23

and then trying to telnet in will show if the connection is getting forwarded or stopped at the router.

I get no response from the Linux server when I run tcpdump and try to access the server through the Linksys router. When I try to logon through the DSL modem using a D-Link router everything works fine. Just no access through the cable modem and the Linksys router.

Then perhaps your cable ISP is blocking port 22. Add a second port in the /etc/ssh/sshd_config, for example:

Port 22
Port 8022

Remember to forward the additional port on the router.

Anything is worth a try. I have a wrt54g and the port forwarding configuration looks pretty foolproof, so it is hard to suspect the router. I guess all outgoing connections from the server are working OK. Not just sneaking out through the DSL interface.

I suppose you could also try cutting the router out altogether and connecting the server directly to the cable modem. That would pretty well isolate the problem to the router.