Connection issues with Steam

I'm using Smart Security Business Edition on 64 Bit Vista with newest updates, initially I had no problems connecting to Steam setting no exclusions within Eset, but recently I've been unable to connect to Steam, the problem is utterly random, for instance I logged in fine last night and this morning, but this evening I keep getting a Connection Error

"Could not connect to the Steam Network, it appears that your are not currently connected to the Internet or that your internet connection is not configured for Steam"

I've followed many tips on the Steam forums about opening ports on my router etc, the Steam Support people seem to have no clue whatsoever, there system seems to be

1. Identify key words (network/connection/error)
2. Enter these words into a Database
3. Copy and Paste link to user

My two year old sister could do that

Are there any suggestions?

 

Hello Avenger11,

Give our gaming performance article and protocol filtering article a try. These articles should free up the blocked communication that is occurring.

Gaming Performance
http://kb.eset.com/esetkb/index?page=content&id=SOLN2229

Protocol Filtering
http://kb.eset.com/esetkb/index?page=content&id=SOLN2132

Thank you,
Richard