You have some service, e.g. webmin, that should not be accessible to the public and block access with iptables? And sometimes you connect from a client that is not yet whitelisted in iptables, and always need to look up its IP and add an iptables rule by ssh. Here is a small shell one-liner that makes your life easier:

iptables -I INPUT -p tcp -s `echo $SSH_CLIENT | awk '{ print $1}'` --dport 10000 -j ACCEPT

This just adds an accept rule to iptables that accepts requests from the IP address of the ssh client to port 10000. Of course, you need to adjust the port. You can just paste this in a bash-script, add a bash alias for it or whatever you want to access it fast.

To remove the iptables rule, just replace -I with -D:

iptables -D INPUT -p tcp -s `echo $SSH_CLIENT | awk '{ print $1}'` --dport 10000 -j ACCEPT

You can create one script or shell alias or for each one for easy access.

If this made your day, just leave a comment.