[Zope] zserver 1 session default?

Trying to access zserver/zope pages: 1. At home I dialed up up my ISP to connect to internet 2. I launched zserver and recorded my ip address 3. I went to work 4. I successfully accessed/browsed my zope pages from my work PC(neat!), but... 5. I attempted to have others access zope from their pc's and NOCANDO? I could continue to access but they could not. Why only 1 incoming ip address for zserver at a time? Using vers 2.1.1 on Redhat Thanks.