Got everything back working as they should be, then I notice this;
I have a network with 3 desktops (2 x Win7 x64, 1 x Win7 x32) connected via ethernet and 1 laptop (Win7 x64) connected most of the time via wireless, along with 3 x Wireless IP Cameras using a Linksys WRT54GS.
I have a desktop statistics program running and noticed very high volume download traffic on one PC (Over .5GB before the computer finished booting, and it's not that slow! and it just continues).
I opened the resource monitor via task manager to see who was hogging the bandwidth and saw it was the "System" process, not too helpful.
But in the connections field I noticed a bunch of connections;
c-XX-XX-XX-XX.hsd1.in.comcast.net - Where XX's are Octets of the IP addresses of my locally connected PC's.
(I am not a Comcast customer. I am in Europe, Ireland specifically, we don't even have Comcast here. I have never installed ANY of their software etc...)
However, after finding that I could view the IP cameras on the network using this Comcast alter-ego, I knew it must be a router problem.
tvnserver - TightVNC's Server process.
Acronis Sync Manager - I disabled this service.
And the System Process. And a few others...
All referring to other systems on the network in this manner.
The IP addresses and Hostnames work as they should, but I can also pull up my webserver locally via this alter-ego. I can also ping them and it resolves with the actual IP.
So on my local network I can use, IP, Hostname, or Comcast alter-ego...
Any idea why my computers are referring to themselves in this manner??
Thanks for your response, but I don't think malware etc is to blame here;
1. I just borrowed a friends laptop, connected it to my network for the first time, same issue.
2. If every device on my network is discoverable/pingable etc from every other device on the network by taking it's IP Address from the format XX.XX.XX.XX and transposing it into c-XX-XX-XX-XX.hsd1.in.comcast.net
That seems like a router/DNS issue to me.
The problem can be seen on any system on the network.
Update: Just had to print something, printer has a static lease. Just after I clicked print I could see the Epson program connect to the Wireless Printer using this format. Was printing from a different PC so it's safe to say it is definitely a Router issue