Habe mal was im Netzt gesucht und gefunden zu demThema was einstellen im Router wenn der Filetransfer nicht mehr geht.
Habe hier mal als beispiel die Routerserie von D-Link genommen aber auch bei den anderen Marken ist es gleich
Leider ist es nur in Englisch, aber dafür mit kleinen Bildern recht einfach und verständlich erklärt 
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To use the file transfer feature in ICQ, you will need to configure your router as well as the ICQ software. The screenshots below are of ICQ 2003a.
How can I find the IP address of my computer?
If you are using ICQ Lite, there is not a way to specify the listening ports so all features may not work unless you enable DMZ on your router. Follow the router instructions below but use port 5190 instead of 20000-20019. To change
port in the ICQ Lite software, go to Main > Preferences and Security > Connection Settings. Click here to setup your router. Remember to use 5190 instead of 20000-20019.
Setup ICQ:
Step 1 Open your ICQ software and login.
Step 2 Click on Main > Preferences > Connections > Server tab. Verify that the port is 5190. Under Proxy Settings, check Not Using Firewall.
Step 3 Click on the User tab, click Not Using Proxy, click Use the Following TCP Listen Port for incoming event and enter from: 20000 To: 20019.
If you want more than one computer to use ICQ at the same time, open ports 20020 - 20039 on computer#2, 20040-20059 on computer #3, etc and then open these ports on your router to the IP address of the computer (see below).
Step 4 Click OK.
Click on your router below for configuration steps:
For the DI-5xx, DI-6xx, DI-704P (revC), DI-704UP, DI-754, DI-764, DI-774, DI-784, DI-804HV, DI-808HV, and DI-824VUP:
Step 1 Open your web browser and enter the IP address of the router (192.168.0.1). Enter user name (admin) and your password (blank by default).
Step 2 Click on Advanced at the top and then click Applications on the left side.
Step 3 Create a new entry:
- Click Enabled.
- Enter a name (icqfiletransfer).
- Enter 5190 in the first box next to Trigger Port. Leave the second box empty.
- Select TCP for trigger type.
- Enter 20000-20019 for Public Ports. This is for 1 user. For 2 users, enter 20000-20039. For more users, add 20 to the last number.
- Select TCP for Public Type.
Step 4 Click Apply and then Continue to save settings.
Note: If your DI-604 screens do not look like the screenshots above, then you have the European version of the router which D-Link USA does not support.
For the DI-704P (revB) and DI-707P:
Step 1 Open your web browser and enter the IP address of the router (192.168.0.1). Enter user name (admin) and your password (blank by default).
Step 2 Click on Advanced at the top and then click Application on the left side.
Step 3 Create a new entry:
- Enter 5190 in the box under Trigger.
- Enter 20000-20019 for Incoming Ports. This is for 1 user. For 2 users, enter 20000-20039. For more users, add 20 to the last number.
- Check the box under Enable.
Step 4 Click Apply to save settings.
For the DI-704P (revA), DI-704, DI-707, DI-711, DI-713, and DI-713P:
Step 1 Open your web browser and enter the IP address of the router (192.168.0.1). Enter user name (admin) and your password (blank by default). If there is only 1 box, enter admin.
Step 2 Click on Advanced at the bottom and then click Special App.
Step 3 Create a new entry:
- Enter 5190 in the box under Trigger.
- Enter 20000-20019 for Incoming Ports. This is for 1 user. For 2 users, enter 20000-20039. For more users, add 20 to the last number.
- Check the box under Enable.
Step 4 Click Save and the click Reboot.