Can you tell if your IM or mail is being monitored over a network?

Question

Is it possible to detect "sniffer" or keystroke recording software or tell if your employer is monitoring your IM & email communications?

Answer 1

If your company is of any size they are monitoring your traffic, to what degree who knows. But you will not know thats for sure. Use encryption between your IM clients, there is software that will provide this, or simply don't use it at work.

Answer 2

If the one who's watching your conversations owes the communication equipment between you and your counterpart, it is not possible to detect it.
The best way to prevent is to use an encryption, based on asymmetrical encryption algorithms. Both you and your partner should install encryption-capable software. For IM there're numerous plugins to implement it (in Miranda client you can encrypt AIM, MSN, ICQ and other messages with single plugin). For e-mail PGP and GnuPG software is usually used.