I have 4 computers and three cameras all plugged in (using a switch) to my router. One of the computers is my webserver (I have a static IP) and I have all the appropriate ports forwarded to that computer. These include HTTP, FTP, POP3, SMTP, WebMail, Shoutcast, and others. When I installed the DIR-601 I started getting complaints that users were having a hard time connecting to my FTP server and even though they did eventually connect, it took forever to transfer any files. I hooked my old DI-604 router (non wireless) back up and everything was OK again. I also have an old DI-524 (wireless) which works OK. I contacted support and they had me update the firmware to 1.01NA. It didn't help. The support person told me to give it about an hour to take effect (this sounded strange to me) and if it didn't work to call back. And, of course, the hour didn't help. All my users have their FTP clients set to Passive Mode. After experimenting with just about everything, I had one of them uncheck the Passive mode option and try again. They connected immediately and file transfers were back to normal. Of course I can contact all my users and have them turn off Passive mode, but I'd rather fix the router to accept it. I know I use Passive Mode for all the external FTP sites I connect to and have no problems with any of them. The DIR-601 doesn't hinder outgoing FTP traffic. I used the contact form on the D-Link site to pass this information on and included the support case number, but I haven't heard anything back. I am more or less of a D-Link fan since I've been extremely happy with my previous ones. Hopefully someone will figure it out and get an upgrade out that fixes it!