Security question (protection against packet sniffer)

I live in a place where several unrelated people use the same router. I heard a rumor (unsubstantiated) that one resident is using a packet sniffer to monitor other peoples internet activity. Is this really possible? If so is there a way to set up the network to avoid a packet sniffer? Can a packet sniffer actually scoop the content of an email? I have no experience with a packet sniffer and don't know exactly what they are capable of, and want to avid the threat if there is any.

Current set up is typical, namely, cable>>>modem>>>router>>>5 computers connected, one wired and the rest wireless. (Cisco wireless g router)All wireless ones use the same encryption key. I have access to the password protected router and settings, but no one else does.

 

Use Tor and encrypt your surfing.

 

Thank you.

 

I'm assuming your connection to the router is wired, not wireless. If it's wireless, I don't know of a solution other than something like Tor - which isn't great.

The easiest solution (wired or wireless) is to just make sure that your important connections (email, etc.) are encrypted using an SSL connection. So if you're browsing, using https:// will only allow the sniffer to see who you're communicating with, not the contents of what you're transmitting. In your email client if you're not using web mail of some kind, there should be an option to use an SSL connection (port 995).

That said, to answer your questions:

is it possible? Yes, but it depends on the make/model of the router you're using, and whether it acts as a switch (data only sent to and from one workstation at a time) or a hub (all workstations see all traffic). A nice description of the difference here.

avoid it? Yes - either use a switch, or encrypt the packets somehow. However, other end needs to decrypt it if you do this.

scoop email? Yes, if they have access to your traffic and connection isn't encrypted. So an unencypted POP connection can be snooped on, but an encrypted SSL (POP or website connection) shouldn't be.

Solutions:

Tor is one way to do it, but its main focus is anonymity of web connections. See the warning page for what it does NOT do. So it you're downloading email locally using an unencrypted POP client, Tor won't help you there.

Another option would be to get a switched router, so that data to and from one workstation is not sent to any others. For all I know you might already have this, in which case your fears are unfounded. This would avoid the problem entirely, as the user would only see their own traffic, not anyone else's. Only thing they can sniff is therefore their own traffic unless they reconfigure the switch. You don't say if your connections are wireless or wired. A recertified wired switch from Tigerdirect.com (assuming you're in the USA) is showing at $40 right now. Make sure you're getting a switch not a hub if you go this route, or all your money will be wasted.

If you're sharing a wireless router, then it's a different issue. I don't know of wireless switches (there might be, I just don't know). I've assumed wired above.