Technicolor router and NAT type Strict on MW3 ??!!
Follow this guide to fix the issue ... worked a treat for me.
Install telnet:
1. Open Control Panel
2. Go into Programs
3. In Programs and Features there should be a section that says "turn windows features on or off"
4. Click "turn windows features on or off" and check the box beside Telnet Client
5. Click OK
OR
download puttytel:
http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html
Bind the ports to the firewall through telnet:
1. Open Run [win + r] enter cmd
2. Enter: telnet
10.0.0.138
3. Enter username: admin
4. Enter password: (leave blank and press enter)
5. Copy and paste the following command lines one at a time and press enter after pasting each:
:connection bind application=CONE(UDP) port=3074-3075
:connection bind application=CONE(UDP) port=3478-3479
:connection bind application=CONE(UDP) port=3658
:saveall
6. Close the telnet session
7. Turn router off for 1 minute, then power on
Not sure if this applies to US members but certainly for any Aus members having probs with new router
