FYI

The solution that I use for remote access with Linksys WRT350N Router is the following.

Do not use port 5001 use 1720 which is for video conferncing (IPS do no block this port)

1. Setup a static IP address for your slingbox (DHCP Reservation)

2. In the router setup window click on the Security Tab  under the name Security there is two sub    tabs  Firewall / VPN Passthrough

Click on the Firewall tab and make sure the SPI is disable and only box that is checked is "Filter IDENT (Port 113) no other boxes on the page should be checked.

3.Now click on the Applications & Gaming Tab.

Click on the sub tab Single Port Forwarding on line six enter the word slingbox or any Id you like. 

Enter 1720 (Externet Port) 1720 (Internet Port)  both (Protocol) your static IP you set for you slingbox 192.168.1.***

Click on the box to enable.

On the bottom of the page click on Save Settings and wait for the page to reload and comfirm all your new settings.

Start your slingbox program and run the Internet Viewing setup once again.

Use the advance settings and manually enter the values you just enter for your router.