This question was originally titled "How to gather information about suspicious wireless access point?" but then this topic has been moved to another question, leaving here discussion of connection problem.
I cannot connect via my network socket - DHCP gives me wrong settings. My guess is that someone in the LAN took my IP address. This is exactly what happened about half-year ago. ISP told that it was their problem, but it took about a week for them to come and fix it. The situation is pretty the same - my socket is not working, but ohter guys seem to be fine. Let me explain the setup and the symptoms:
Our ISP is the main provider in the area where we live. They installed hardware in the buildings and other providers will use it if we want to switch to them. Moreover, by contract with the landlord we have pay to both the main ISP, and to whatever ISP we want to switch to.
Everyone has one socket per apartment and one IP address provided via DHCP. I have lived in several apartments in the area, and there is always an issue with assigning IP - it takes several days before a new device is given the correct settings via DHCP. Everyone experiences this and I have tried to tell this to ISP - no reaction.
Since we have more than one device to connect to internet, I had to buy a wireless AP and I have chosen a cheep DWL-G700AP of not very high quality as you can see from this wizard emulator. It is not a router, so it assigns an IP in the LAN using ISP's DHCP.
I live in a student area and I believe quite many guys use such cheep AP w/o routing. Since the ISP's settings are quite old, I suspect that the mask of 255.255.255.192 doesn't correspond to the reality when almost every household has about 5 devices requiring own IP address.
Sometimes I loose internet connection via my AP. It can be several times per day, or once per week. The solution I came up to is to turn off/on my D-Link.
This suspicious AP, which I am using now instead of my AP, has also 54Mbps but it works few times faster. I am impressed.
And yes, no surprise, that we loose the connection right when we need it so mad - just before course examinations or project deadlines.