If you have a dynamic ip, it is difficult to ssh into your box - considering that the ip today might not be the ip tomorrow. I had the same problem - I was able to ssh into my home box from work box until the ip addresses were changed. My advice is this - either
(a) buy a dynamic ip from your isp
(b) register a domain and register with www.zoneedit.com
. Point your domain at the zoneedit nameservers (it's all explained in the documentation on zoneedit) and - hey presto - you will be able to telnet/ssh to your domain (e.g. ssh mydomain.com). You'll need software to update zoneedit about your dynamic address changes - info on zoneedit. Note - be careful where you register your domain. Be sure that they allow you to use your own (ie zoneedit's) nameservers.