Ok, so I've had this problem for quite some time, and have searched quite a bit for the past few days as well as several other times in the previous year, but have not came up with any information to help me.

I got a Linksys BEFW11S4 router (wireless with 4 port switch) and it will block ports i.e. 80, or whatever port I open up to host sites or FTP's, but this seems to be intermittent occassions.

Occasionally it will allow connections, but usually it will refuse them. I have opened every port in port Router's Port Forwarding page, and have also tried in the UPnP Forwarding page. I have disabled the "Block WAN Request" Filter, but that doesnt happen to make any difference. I have even set my hosting box to be the DMZ Host, but yet that has no effect either.

I have upgraded the firmware several times to the newest version. The one thing I am uncertain about though is the SPI, but from what I understand, this feature has been removed so that doesnt matter.

My ISP doesnt block port 80, and this happens to me no matter what port i happen to use, so I dont feel it is anything else than my Router.

If anyone would happen to know how to help me out, I'd surely appreciate it.

Thanks, Brian

Are you using a static IP or dhcp for the PC your fowarding the port to?
It should be configured as a static IP address. I would venture that 99% of the time in a small network of a couple of PCs your always going to get the same IP address but if it changes, port forwarding will not work.

Have you considered this just to be a faulty router. Have you checked with linksys on the problem? IMO there tech support is very good.

Hey, no its not IP related, I use 192.168.1.10 for my Desktop computer, and 192.168.1.20 for my laptop, so thats ruled out. I don't believe the router is faulty, but I will contact Linksys tommorrow and see what they happen to say.

Thanks, Brian