Why does this happen?

A customer brought in a computer that had several problems. This Is a Windows Vista x86 machine. The machine has Mcafee Security suite.

 

I left the machine on overnight. All machines were setup on the “workgroup” workgroup.

 

I noticed this am that this Vista had reached out to the other machines on the same network and determined that these machines needed a new security suite on them. McAfee stated that I needed to purchase their security suite.

 

How can Mcafee reach across my network and determine which Anti-Virus I had?

 

If Windows allows this activity, why can’t any other program do this?

 

Or is this activity caused by flows in my firewall or current AV?

 

Machines – Windows XP with Zone Alarm firewall with Microsoft Security Essentials

Windows 7 with Norton Internet Security 2011.

Machines are fully patched.

 

Why?

 

Thanks