I'm posting this as a result of a long discussion that I had with someone yesterday.
To cut a long story short most (but not all) of my on line connecting is via extended wireless link. I have, like all the rest of the faculty/students, wifi access into the campus system, i.e. I can sit with my laptop anywhere in range, library, cafe, plaza etc etc and log in and be online to my hearts content.
About 1KM from me is a small extension unit and some residences associated with the main campus. This has Wifi access into the main system as well. My residence is line of site the other side of a small deep valley. I reasoned that with enough antenna gain I could connect into it. I have some basic experience in RF design and construction and set about the task. After some initial teething problems I achieved my goal with a high gain helical antenna. Ironically its better in winter when theres no leaves on the trees. However, it pretty reliable now I removed some branches of a tree next to my house. Only when its wet and windy does the signal strengh get reduced slightly.
To return to the main point. When I talked about this with my friend over coffee he said I was taking a huge security risk. I explained that the beam width of this antenna is --extremely-- narrow (like I have to have it rigidly clamped so the wind does not vibrate it off alignment). Still he was unconvinced. I view this essentially as a large WiFi router, just that its a ways off. The security in place on the campus system is from what I understand pretty tight. Then theres the security on my system.
But I would be interested to hear any perpectives or thoughts any of you may have on this. All of this of course refers connecting in using Linux.