blacklisting noreply@blizzard.com, does it work to stop spammers?

[Deleted]

now, i checked and rechecked, and the address "noreply@blizzard.com" isn't one used by Blizzard (i believe they use one of these: http://eu.blizzard.com/en-gb/company/about/contact.html). so can i safely block any emails coming from "donotreply@blizzard.com" or "noreply@blizzard.com"?

maybe something even more advanced: I want to block all emails that end in @blizzard.com, but don't come from any of the following mail servers:

Blizzard US
DNS: ob3.blizzard.com 
IP: 216.148.0.68 

Blizzard EU
DNS: eu-smtp02.blizzard.com 
IP: 80.239.172.105 
Or 
DNS: eu-smtp01.blizzard.com  
IP: 80.239.174.216 

Blizzard insider
DNS: info.cme.vugames.net 
IP: 12.129.240.41 
Or 
DNS: email.blizzard.com 
IP: 12.129.200.219 

these are the mail servers that are officially used by blizzard, i doubt anyone can send a mail like it comes from these servers.

[Cilraaz]

In theory, it would work. In practice, nearly any part of the email header can be spoofed. Also in practice, not many spammers bother spoofing anything but the From Address.

[Deleted]

but what about my second part: is it possible to block all mails from a certain domain that aren't from one of those 5 IP addresses?

[Cilraaz]

That totally depends upon your email system.

[llDemonll]

http://min.us/mFMy5yOvn9sYJ

All of those are legit blizzard emails. Yes, I've been hacked before. I put dates to show that they have been used recently, the october third was a friendly reminder to let me know blizzard wanted more money from me

edit: all of the 'noreply' are from 'noreply@blizzard.com'