Comcast provides the connection. Do they issue the IP #?
If so, is it likely they can change it?
They will give you a static IP address if you pay for one. Generally this involves getting a Business account connection.
You can try disconnecting your Comcast cable modem from the cable for a few hours, and maybe Comcast will reassign the IP address you were using to another customer, and give you a new one, when you reconnect your Comcast cable modem back to the cable. Then again, they may just give you the same IP address again, as they may have it locked to your cable modem's identifier. Your mileage may vary.
Thanks for the reply.
If I were not using a router, but had two different mac's and connected them alternately to Comcast. would the both have the same static IP address?
And if I added and connected a lap top would it also have the same IP address
all because it is one common connect to Comcast? and not the computer that is the determinent?
Comcast provides the address.
The address is not static, in the Internet sense of the term. But Comcast dynamically assigned IP addresses tend to be stable, until they are not.
I do not know what Comcast uses to decide the address to assign to your cable location, nor what will make them reclaim the IP address and assign it to someone else.
Since you have been direct connecting you Macs, you can check you assigned IP address via system preferences -> network -> Ethernet -> advanced -> TCP/IP, or use http://whatismyip.com, Google "my IP address"
If you IP address does not change, then chances are Comcast uses your cable modem to identify your location, and is just reassigning the same stable IP address to you. Disconnecting the cable modem from the cable may cause Comcast to reclaim the IP address, or not.
Turned out that the problem was in the software Net Barrier from Intego.. where a special setting needed to be made to allow one to act as a 'server' to the other...After making that change any computer on the network could connect to any other.
In hindsight, it is obvious it was a learning process at age 86