[Kuwaiti Kid]

I am new to Red Hat Linux and have been trying to install a Shell Script I found on the internet using vi.

When I try to run the script I get an error message "Bad Intepreter" and don't know what to do to fix the problem. I have copied the Shell Script exactly as it is shown.

I am sure the answer to this is very simple and any help I can get would be very much appreciated

[Squashman]

Can you show me the script?
What are the permissions on the file?
Is it a bash script?
What is the path to bash on your system?

[Kuwaiti Kid]

This is the file I wrote. It is a Firewall and is also meant to link a second computer to the internet through the first:

!/sbin/sh
#firewall.sh
/sbin/iptables -P INPUT DROP
/sbin/iptables -P FORWARD DROP
/sbin/iptables --flush
/sbin/iptables --delete-chain
/sbin/iptables -P FORWARD DROP
/sbin/iptables -P INPUT DROP
/sbin/iptables -A INPUT -i lo --source 127.0.0.1 --destination 127.0.0.1 -j ACCEPT
/sbin/iptables -A INPUT -m state --state "ESTABLISHED,RELATED"-j ACCEPT
/sbin/iptables -A INPUT -p icmp --icmp-type destination-unreachable -j ACCEPT
/sbin/iptables -A INPUT -p icmp --icmp-type time-exceeded -j ACCEPT
/sbin/iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
/sbin/iptables -A INPUT -p icmp --icmp-type echo-reply -j ACCEPT
/sbin/iptables -P FORWARD ACCEPT
/sbin/iptables -t nat -A POSTROUTING -o eth0 -J MASQUERADE
echo 1> /proc/sys/net/ipv4/ip_forward
/sbin/iptables -A INPUT -j LOG -m limit --limit 40/minute
/sbin/iptables -A INPUT -J DROP
/sbin/iptables-save > /etc/sysconfig/iptables
echo "$0: Done."

[Kuwaiti Kid]

This file is located in the sbin directory and to set the permissions I used chmod u+x

[Squashman]

Are you sure the path to SH is in /sbin. It is not on my Red Hat 9 box. My default shell is bash so I don't even bother with the first line in my firewall script.

The first line should look like this
#!/bin/sh

[Kuwaiti Kid]

When I change the first line to #!/bin/sh and I run /sbin/firewall.sh I get the following error:-

sbin/firewall.sh: line 1; !/bin/sh: No such file or directory
iptables v1.2.7a: Unknown arj '-J'
Try 'iptables -h' or 'iptables--help' for more information.
iptbles v1.2.7a: Unknown arg '-J'

[short101]

First line of the script should read
#! /bin/sh
not
!/bin/sh
I think you may have just missed the # when you copied it.
Writing iptables rules isnt something that I would take on lightly. You really need to know what you are doing otherwise your leaving your box open to attack. If you dont know what you are doing, I would suggest using a frontend like firestarter or guarddog.

[Squashman]

I don't even think he needs that in the script if the default shell is sh or bash. I do not have it in my Iptables firewall script and it runs just fine.