How can i tell if my iMac wi-fi or if my router has been hacked?

Thanks for a quick reply.

Had this issue before I installed AVAST. In fact, I installed AVAST to see if antivurus I could identify something on the machines. They haven't. I'm not against removing it, but don't see it as part of the problem. In fact, I have this issue on a fresh install of lion with nothing else installed except chrome. This is why I am suspecting that I have been hacked. Seems reasonable to suspect the router.

Any other ideas?

Thanks in advance for your responses.

jw

Also, when you get back to me . . .

How do you suggest I re-test? So far I have only made observations. I have been using macs for 5 years, but have not really encountered any problems before this, so I haven't ever run diagnostic software and am uninformed as to what to use that would address this type of problem.

Thanks and I will watch for a reply.

Thank you all for your responses.

This never happens to the PC my wife uses, and I have a MBP that I bring home from school and it doesn't happen on that machine. I get the discussion of the replies about how safe OSX is from virus et al, and the install of AVAST is temporary and just another idea that I have tried. So thank you all for your urging me to keep my macs pure and clean. I do believe in that and have practiced it even in the face of IT people at the school district level who have insisted that I must have antivirus/malware protection on my MBP if I plan to connect to the network at school. That MBP does have AVAST, but only because school IP people will block my mac address if I don't have something installed. Ironically, that is one of the macs that doesn't behave the way my 27" the 21.5 and the old 20" do. I also have an old MBP (late 2008 17") that does not have this problem.

I do have a neighbor whose routers I see whenever I look at the available connections, however her router has always been there (for years), and this problem has surfaced around Thanksgiving time. I totally wiped the hard drive on the 21.5 and reinstalled Lion to see if a different version would behave differently, but it behaved the same way. I have two repeaters/extenders in my 6000 ft home. I have not set my iMacs to ignore the neighbors routers. I think I know how to do that.

I don't think it is related (unless the hub is the villain), but my Samsung SMART TV (which is hard wired to the cisco router) has begun behaving badly since the Jonas snowstorm here in the east: The HUB will just kick the TV off the network: i.e., when I am on AppleTV watching CNN or other. Also, sometimes the HUB won't open and I have to try several times. We have been kicked out of Netflix and Pandora also, but again, this is recent with the TV and the computers have been doing this since before Christmas. So, dialabrain, your suggestion that there could be an issue with transmission lines makes sense. But all the lines are buried up to my home and are in conduit coming out of the ground. I don't have mice in my home (and I'm not just denying how pesky varmints can be-- I have both traps and bait and a beast of a Maine Coon cat who kills any rodent that moves in its presence).

It feels like I should be thinking about the router. I will see what Cisco has in the way of a support community and will post back here if I find a solution.

I apologize for such long posts. I will try to be more direct and concise if there are other replies.

Thanks for your input. Thanks in advance for your thinking on this problem with me.

jw