hi frns,
i'm using rel server 5 and rel desktop 4 connected through lan,i can ping from either side,i logged through ssh from rel 4 to rel 5,but can't login from rel 5 to rel 4.what may b the problem? i started the sshd services on both the machines,the sad thing is i can't find a line ssh 22/tcp in /etc/services in rel 4,so i add that line and restarted the service ,but again the same problem.......help me

Is the ssh server running on the RHEL4 machine? You can verify using one of the following:
Take in mind that on RHEL4 the openssh-server is not installed by default.

check your iptable whether it is blocking ssh (port 22) at your rhel4

This might be possible due to either ssh is not installed or properly

configured on your RHEL4 box. You can follow these steps for

checking whether ssh is installed, configured and running properly or not

below is the sample from my RHEL box,

1.Check whether rpm is properly installed on your RHEL 4 box by

issuing this below command:-
[root@linuxserver1 ~]# rpm -qa | grep ssh
openssh-4.3p2-16.el5
openssh-askpass-4.3p2-16.el5
openssh-clients-4.3p2-16.el5
openssh-server-4.3p2-16.el5

2. Check ssh script.
[root@linuxserver1 ~]# vi /etc/ssh/sshd_config
# $OpenBSD: sshd_config,v 1.73 2005/12/06 22:38:28 reyk Exp $

# This is the sshd server system-wide configuration file. See
# sshd_config(5) for more information.

# This sshd was compiled with PATH=/usr/local/bin:/bin:/usr/bin

# The strategy used for options in the default sshd_config shipped with
# OpenSSH is to specify options with their default value where
# possible, but leave them commented. Uncommented options change a
# default value.

Port 22
#Protocol 2,1
Protocol 2
AddressFamily any
ListenAddress 0.0.0.0
#ListenAddress ::

# HostKey for protocol version 1
#HostKey /etc/ssh/ssh_host_key
# HostKeys for protocol version 2
#HostKey /etc/ssh/ssh_host_rsa_key

3 check sshd service running or not
[root@linuxserver1 ~]# /etc/init.d/sshd status
sshd (pid 3112 3022) is running...

4. Run netstat command whether ssh is listening all ip addresses on 22

port (ssh works on 22 port).
[root@linuxserver1 ~]# netstat -tulpn | grep sshd
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN

2456/sshd

Note: If you have allow only your home/office ip address for sshing in

ssh_config script. netstat will show that ip address.

5. Also you may check whether firewall is not blocking 22 port by issuing

this command
#iptables -L.
If firewall is enable 22 port should be ACCEPT in INPUT option.

Hope this will help. Also you can paste the error message which you get

while sshing from rhel 5 to rhel 4 box this will shed the light on this

problem more clearly.

RGD
Charanjit Singh
RHCT