This summer I was able to take a wonderful two-week trip abroad with my family. One day during the trip I realized that I had a dangerous (=expensive) setup in my terminal:

• lots of applications doing automatic network operations
• every application has roaming check turned off (reason is here, in my older post)
• all applications are set up to download as much as possible, because I have a flat-rate data plan when at home

My first reaction was that I started to launch applications and manually changing their network settings. After doing that for a while I got frustrated when I understood that same project was waiting for me when I get back home, in order to allow network traffic again. Then I got an idea how to make sure my applications are not doing unwanted network operations (which would cost in a worst case something around 10€/MB).

This trick worked fine at least in my E61: I opened the terminal's access point settings (Tools->Settings->Connection->Access points) and created a brand new access point by copying the settings from my previous access point (Options->New access point->Use existing settings). I renamed the new AP to "travelling" so that I could find that easily. Then I opened the settings of the AP that I had configured to all applications and made that AP invalid by making a minor change to setting field "Access point name". Now I was sure that there weren't applications opening network connection unless I explicitly allowed it to do so by selecting the new AP - if an application tried to use old AP it didn't work because of changed AP name. When an application tried to make a network connection, it either failed with broken AP ("Packet data connection not available") or application prompted for new AP.

Returning to "home network" was now easy; I deleted the AP named "travelling" and returned the original AP to its correct settings. Applications found network again and those applications I had allowed to use network abroad prompted for new AP to replace the missing one.