If you do a reverse IP lookup on your dynamic IP, you'll probably see that you have a DNS string. For most, but not all ISPs, this DNS string is invariant and, more importantly, will always resolve to your then assigned IP address.
In my case, my dns string is
Code:
CPE<pc's_mac_address>-CM<modem's_mac_address>.isp.domain.com.
(e.g. CPE00099a711234-CM00099b117c43. ... .com)
Therefore, I can
always hit my box via ssh by using
Code:
# ssh s2scott@CPE00099a711234-CM00099b117c43.myisp.com:22
Try finding out your ISP's dns string
http://www.whatsmyip.org has some useful reverse lookups.
/S