First, let me get out of the way that I am a total Linux newb and this is my first real experience installing and configuring a server. Now onto my problem.

I just installed RHEL 5.0 and I am having issues connecting through ftp clients, Exceed xterm, and telnet from a remote client. As it stands the only type of remote connectivity I have is through an SSH Putty connection.

Problems:

Telnet - From Windows, when I try to Telnet to the linux box I immediately receive a connect failed message

C:\>telnet xxx.xxx.xxx.xxx 23
Connecting to xxx.xxx.xxx.xxx 23....Could not open connection to the host, on port 21: Connect failed

FTP - I've tried using a GUI (FileZilla) and a command window to access an FTP session but it almost immediately fails

ftp> open xxx.xxx.xxx.xxx
> ftp: connect :Uknown error number.

When using FileZilla it immediately throws me a "Could not connect to server" error when attempting to connect through port 21.

Exceed - Pretty much any connection method attempted to establish an x-window session fails upon failure to reach the host.

The client machine I am using is behind the same firewall as the server. I installed RHEL through the GUI installer, and I initially configured the firewall to pass through Telnet, FTP, etc. Trying to troubleshoot, I disabled the firewall and stopped iptables but this did not help. Can someone please point me in the right direction?

I'd also like to mention that I can make an sftp connection from another RHEL 5.0 box to the problematic machine without a problem.

Can you nmap the server and be sure that it's listening on those ports? If it isn't you may need to start or restart the services.

nmap <server ip address>
nmap 192.168.1.25

this should show all ports that the server is listening on.

to restart a service:
/etc/init.d/<service> restart
/etc/init.d/telnetd restart

1. check the firewall on the server with
iptables -nvL

2. telnet server is normally disabled by default due to security issues ie plain text transmission.
You may need to install it

yum install telnetd

then go into /etc/xinetd.d and edit the telnet file, set 'disabled=no', restart xinetd service
You'll need to check /etc/hosts.allow,deny files as well.

Personally I wouldn't use a telnet server without a very good reason.

I'm assuming
is a typo; if you telnet to port 23, you won't get an err msg about port 21