I have 1 corporate office and 8 remote locations. The corporate office has approx 12 Xp boxes. The remote locations have 2-4 Boxes. Our email is hosted by AT&T (Neomail). We use a combination of outlook and outlook express set up for pop3. DSL internet connections with NAT.
I currently have 3 seperate locations (IP's) that are blacklisted. 2 locations have been blacklisted numerouse times. All of the computers have antispyware and antivirus protection(mostly the free stuff). Each time a location gets blacklisted, I either run the scans and find the bugs or re-image completely. We come off the blacklist for a month or so then get blacklisted again.
Do most spambots come via spam emails? I know it is my responsibility to keep my boxes clean but does the hosting mail server have some responsibilty in this also? If so, what can I resonably expect from them? Does anyone know of a way to narrow down the exact box that is spamming?
This is a small retail chain and IT budget is limited to non existent. I would greatly appreciate some advice.