unable to ssh my machine in any way - any ideas?

mr_furley · 07-02-2006, 03:04 PM

Thanks Jim.

I found that if used 'su -' instead of 'su' the 'iptables' command works fine. Why is this?

I ran
`iptables -I INPUT -p tcp --dport 22 -j ACCEPT'
again, and everything is working fine now. It seems as if after I reboot, the ip tables revert back to some default configuration. How can I fix it so that I don't have to rerun 'iptables...' every time I reboot?

Thanks!

D

GTSI_Jim · 07-03-2006, 05:09 AM

As for the su - problem:

The hyphen has two effects: (1) it switches the current directory to the home directory of the new user (e.g., to /root in the case of the root user) and (2) it changes the environmental variables to those of the new user. That is, if the first argument to su is a hyphen, the current directory and environment will be changed to what would be expected if the new user had actually logged on to a new session (rather than just taking over an existing session).

Thus, administrators should generally use su as follows:

su -

An identical result is produced by adding the username root, i.e.,

su - root

As for the iptables issues:

iptables stores its config data from one boot to the other. Try doing an iptables -L after reboot to make sure. You probably need to issue an iptables-save after ou add your rule to ensure that this save happens.

Good Luck!

Jim

Notwerk · 07-03-2006, 09:00 AM

Another way to make sure your changes to iptables are saved is by using:

Code:

#/etc/init.d/iptables save
#/etc/init.d/iptables restart
#iptables -nvL | grep 22

This will save the current configuration of iptables to be the defualt one used whenever the machine is booted. Then it will restart the firewall. And finally look for any rules containing the value (22) (the default ssh port number) and report if any exist. It might result in additional lines if they also contain the value 22.

Good luck