If you’re trying to run an app that requires TCP connectivity and find it to be mysteriously failing, then probably your BlackBerry is missing it’s APN settings. See Options -> Advanced Options -> TCP.
There are four recommendations floating around the net. So far, this works for me:
APN: wap.cingular
Username for APN: <blank>
Password for APN: <blank>
Other allegedly successful access patterns, eg:
APN: <blank>
Username for APN: <blank>
Password for APN: <blank>
APN: proxy
Username for APN: <blank>
Password for APN: <blank>
APN: isp.cingular
Username for APN: <blank>
Password for APN: <blank>
would appear to be lies and damned lies.
On the backend, bad APN’s will fail with “Invalid tunnel name” if the device can’t figure out what type of network connection you’re trying to use, otherwise “Open tunnel – failure” if it thinks it can connect but authentication fails.
…
Oh BlackBerry people, why have you made basic networking so complex? We at our little startup are starting to think we can’t afford to support network-enabled apps on your devices. Life is so much easier on the iPhone…
Actually, another (rumor|lie) that I saw is APN: public, Username: , Password: .
I am debugging a Blackberry app, and have torn my hair out trying to get the APN settings right for t-mobile (wap.voicestream.com, followed by much yelling and screaming at their support line to actually activate it) and AT&T (wap.cingular works for me too). I never thought I’d say this, but Sprint actually does it right. Their Blackberry works, slow as a dog, but without configuration nightmares, on their iDEN network.