Changing IGMP settings messed up Internet access
I configured my server to run NAT and am able to access the Internet from my server. Experimenting, I went to routing and remote access /server/IP Routing/IGMP/ and selected the local area connection properties. In the General tab I switched to "IGMP router," saved and tried to access the Internet; I could not. I went back and changed the setting back to "IGMP proxy," but I still could not access the Internet. I checked all my DNS and DHCP and all seemed normal. I have two NIC cards one that goes to my ISP and the other that goes to my network. My question is: What setting(s) got changed when I made the switch and then went back that don't allow me to access the Internet, and how can I change then back without having to reinstall my server OS?
IGMP is used for multicasting, so if you're not sure what it is, you probably don't need it. I don't know of any particular problem that enabling IGMP routing would cause. However, I have had problems with RRAS when I made configuration modifications that shouldn't have affected anything. I would start with the same first step in any troubleshooting process: reboot the computer. In my experience, no incarnation of RRAS is terribly reliable, and rebooting solves these transient problems.
If that bit of brilliant advice (forgive the sarcasm) doesn't solve your problem, then you can either spend a few hours understanding in-depth how RRAS works so you can isolate the problem, or you can spend a few minutes uninstalling and re-installing it. Good luck! I wish it were something that were simpler to troubleshoot so I could offer more tangible advice.
This was first published in September 2002