Why can I connect to some but not all unsecured networks?

Question

When I travel, I hate to pay the $10 - 12 per day for the hotel service but will when there is no other choice. In most any populated area there are often numerous secured and unsecured networks.

I wouldn't expect to ever be able connect to secured networks but I would like to better understand how unsecured networks work.

I will find that I am able to connect to some unsecured networks but not most. Its not dependent on signal strength so how do they vary?

Is there something I need to do to connect to some unsecured networks that is not necessary for others?

Please do not bother going on a rant about stealing someone's bandwith. Often these networks are provided to the public by coffee shops, the city, libraries, etc. They are intended to be used by the public. Additionally I leave my home network unsecured when I am not using it for the benefit of others. When I am using it, I re-secure it. Is there any risk in doing that?

Answer 1

Some of it may be distance, or materials inbetween. Just because your computer can see the network doesn't mean it will be able to pass enough traffic over it to hold a connection. Some unsecured networks may not use DHCP, but instead have static addressing. That is, the wireless router may not give you an IP address, but you may have to know what address and gateway to use in order to use the network.

Bottom line is that it's really hard to tell you why you can't connect to a network when we don't know how it's set up, but there are quite a few different reasons that are possible. I won't get on about the stealing bandwidth (as I remember being mildly upset when my in-law's neighbors secured their wireless network and I couldn't surf at high speed when visiting them anymore), but when you do count on using free wireless access that you haven't arranged beforehand, sometimes you get exactly what you pay for. :/

Answer 2

toforama's answer is fairly good. Many unsecured networks aren't really unsecured they may be using MAC filters or some other authorization systems that "show" as unsecured but actually use validation of some sort. (PPOE like with dialup etc)

As far as leaving your system open for others... if some one sends out a few million emails from your IP guess who gets blamed, or they surf porn, or uses your access as a "scam port" guess what.. you have to defend yourself because YOU authorized that use by leaving it open... Now do you really want to do that?