Subj : Re: Monitoring FidoNet
To   : August Abolins
From : Kurt Weiske
Date : Thu May 27 2021 07:02 am

-=> August Abolins wrote to John Dovey <=-

 JD> ..and I'm fighting with my ISP to allow me to create a DMZ
 JD> where incoming traffic is allowed.

 AA> I thought that's how most ISP worked these days. Then your own
 AA> router provides the firewall/isolation required.

In a typical setup, you have one publicly accessible IP address on your 
router. Your router uses a private address space for the systems on the 
inside and the router uses Network Address Translation (NAT) to share that 
one public IP address among many systems. The router manages connections and 
keeps the traffic going to the right system on the inside.

The router can use port forwarding to pass on inbound traffic on specific 
ports to a specific system, for example, sending telnet traffic to your BBS.

Some ISPs use "carrier NAT", which means you get a private address from the 
carrier, and they do their own NAT upstream from you. It's pretty 
transparent to a web browsing user checking their mail, but it means that 
you can't port-forward, since people on the outside can't get to your 
system.




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