[ubuntu-users] Security and Intrusions

[Ted Hilts - Thunderbird Acct.]

This email not about Thunderbird but I use Thunderbird as an example.  I 
noticed that when using Thunderbird mailer some of the "cc" alternatives 
in the prompt field were not mine nor anyone I contacted. I currently 
operate with no firewall active for the machines in my LAN because I am 
trying to address some issues that the firewall complicates.  So I am 
***not*** asking about how to set up a firewall.  I am asking the 
following: "How do I establish if I have an intruder using my LAN 
resources"???.   Recently I have seen the operation of one of my LAN 
machines get slower and slower while there is little or no change in the 
performance of other LAN machines.

Also, a related issue: How do I establish if a slow down of processing 
on my LAN computers is due to:

1. A problem within the LAN itself.

2. or a problem on the Internet:
 due to congestion of the route available

3. or the slowness of a certain server passing data to my LAN(down for 
maintenance or simply overloaded and dropping clients)

4. or one of the ISPs throttling (restricting) bandwidth (I know that 
Bell Canada sells bandwidth to my ISP (I am in Canada) and Bell has been 
identified in the news as doing this and has been before the CRTC to 
justify it's behavior.  Also, a British ISP has engaged in this behavior 
according to the news.  My ISP says that Bell's behavior does not affect 
them and therefore does not affect me.  However, in a recent news 
article one of Bell's associated ISPs (who buys bandwidth from Bell) was 
restricted by Bell in the use of that bandwidth during certain times.

I ask these above questions because I encounter numerous slowdowns and 
drop offs affecting my LAN (some requiring reboot) as well as certain 
LAN machines going almost dead at one time and then booming along at 
some other time or one machine in particular doing very little while 
another machine is doing a lot. Based on the list's discussion on SSH I 
know there are people on the list that can answer these questions. My 
LAN has both Windows and Linux machines. I really need to get some kind 
of handle on all of this.  Is there an application somewhere that can 
track all of this so that it is obvious to ***me*** (retired -- old and 
getting older -- forgetful and getting more forgetful -- dumb and 
getting dumber -- with one foot already in the grave).

Thanks -- Ted