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Message: [QUOTE="Dave Brueck, post: 1726885"] The problem with the InternetGetConnectedState API is that, at least on older versions of Windows/Internet Explorer, it relies on the settings of Internet Explorer rather than the true state of the connection. In other words, it would return an incorrect answer if Netscape was the only browser ever used. Also, it doesn't work in a connection sharing setup (e.g. your computer is on a home LAN that is connected to another computer with a modem. Maybe this is way more than the OP needs, but I'll post it anyway because it's tough to reliably detect the connected state. After much painstaking experimentation :) I came up with a fairly decent method of knowing if the current computer is really connected to the Internet using a combination of all sorts of info available (works on Windows using ctypes). It turns out that there is no single API to call, and some APIs give unreliable info, and others will cause your modem to go online if you're not online, so they must be avoided. Here's a breakdown of the determination process that works for me: - First and foremost, if your application is currently downloading or uploading then you know you're online. At first it seems silly, but it's actually a pretty reliable nugget of info, so my connection detection lib has a SetOnlineHint(isOnline) API that the app calls periodically (internally my library uses an exponential moving average to "degrade" this value over time so that if it falls below some threshold then the library doesn't consider it to be accurate enough to rely on and moves to the next method of detection). - Call the GetTcpTable API and get a list of all IP addresses whose rows have the dwState of MIB_TCP_STATE_ESTAB. Then filter out all IP addresses 127.0.0.1, 10.* 192.168.*, and 172.16* through 172.31.*. If the remaining list is non-empty, something on this computer is most likely connected to a public IP address, so it's fairly safe to assume you're online - If RasEnumConnections gives a non-empty list then you're online (but don't assume the converse is true) - If the IsNetworkAlive API is supported and returns false, you're not online (But you can't rely on a "yes" answer from this API) - If all the above don't yield any definite answers, then ping a known IP address (either by using raw sockets or by just calling os.popen('ping ...') and reading the output. Ping is nice because ICMP packets won't cause the modem to autodial if you're not online. My library has as a default the IP addresses of a bunch of well known servers (e.g. DNS root servers) to use in emergencies, but these are best avoided in all but the most extreme emergencies when it has no other IPs to use - it collects public IP addresses from the GetTcpTable call above, for example. The library runs through this determination process every second or so in its own thread, pinging at most once every 5 or 10 seconds, and the application just queries a IsOnline API. Convoluted, but it works, so it was worth the effort to put it in a separate library and never figure it out again. :) -Dave [/QUOTE]

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