How do I configure dynamic DNS when my router does not support it? I have a MacBook which is connected to the net via an ancient DSL router (NAT enabled). I want to SSH into the server from elsewhere, but my ISP assigns new IP address every once in a while.

I would like to use a dynamic DNS service for "finding" my Mac, but the router does not support any dynamic DNS functionality.

What (lightweight) option is there to update the DNS service with current IP info anyway? I remember installing a clunky menu-bar app several years ago, and I would prefer something configurable from the terminal.

NB: I feel it could be a problem when the MacBook is moved to a different network (friends, company) temporarily and attempts to connect to macbookaddress.dynamicdnz.tld suddenly hit their network. Correct?
ddclient is what I use on my Linux boxes. Works really well.

You can find instructions details here: http://sourceforge.net/apps/trac/ddclient

I think all you would need to do to get ddclient to run is to a @reboot line to your crontab and you’re set. 

crontab -e


then add this line:

@reboot /usr/sbin/ddclient -daemon 300 -syslog