Mac OS X TCP/IP Routing
September 16, 2004 12:44 PM Subscribe
Mac OS X TCP/IP routing filter! I have two network interfaces on my Mac. I want most of my Internet traffic to go through my NAT router, but still allow the machine to be accessible from the Internet at its own address. More inside...
posted by kindall to Computers & Internet (23 answers total)
I have two Ethernet interfaces in my Mac because this lets me connect to my second computer, a Windows box, behind my hardware firewall/NAT router while at the same time giving it a real TCP/IP address (my DSL package gives me two). However, recently I switched to Vonage for my phone line. Now I want to run most of my Mac net use through the firewall/router so that it goes from there through the Vonage adapter so the adapter can do its voodoo to prevent dropouts on the voice line. Switching the Mac over to go through the router was easy, but now, although the other interface with the "real" TCP/IP address is up and accessible on the LAN, it can't be connected to from the Internet. My guess is that the packets get from the Internet to my Mac okay, but when reply packets go back out, the Mac is sending them out through the NAT router instead of from the interface they came in on, which makes them appear to come from the wrong IP address, so they are discarded.
Now I could set up the firewall/router to open a few ports (SSH, etc.) to my Mac instead of my PC, which is what I'll do if I can't figure this out. But since I have two IP addresses, I'd really like to give the Mac its own. Is there any way to get this to work?
This is kind of a complex situation so if I need to clarify anything, just ask.