How do I block port 25 on local pc in a domain?

A co-worker was surfing the web, and it installed a Trojan that send thousands of emails within a short period of time.  Needless to say, our IP address is blacklisted by:
Connection refused due to abuse. Please see http://mailspike.org/anubis/lookup.html

My question is, what do I need to do, at each computer, to prevent it from sending mass e-mail messages?  Currently Symantec EndPoint Protection is running on all computers, and the co-worker did receive a "warning" from Symantec that a trojan may be running and sending out e-mails on a proxy server.  

By the way, I have submitted a request (at least 8 times) to mailspike to delist my IP address.

Thanks for your help!
LessonsLearnedAsked:
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MMTadminCommented:
windows firewall block port 25

or

router block port 25
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LessonsLearnedAuthor Commented:
Can I use Windows firewall AND Symanec EndPoint Protection at the same time?
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JohnBusiness Consultant (Owner)Commented:
Can I use Windows firewall AND Symanec EndPoint Protection at the same time?

No. This is not a good idea and SEP will disable Windows Firewall.

The best place to do this is block port 25 at your firewall. I have done this a my clients (Juniper Netscreen firewall) with no ill affects.

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CoffinatedCommented:
Your best bet is to block port 25 on the firewall as the malware can control infected PC and could unblock port 25.
If you decide to block port 25 on every PC, do so using group policies

Another option would be to invest into application layer firewall


The key benefit of application layer filtering is that it can "understand" certain applications and protocols (such as File Transfer Protocol (FTP), Domain Name System (DNS), or Hypertext Transfer Protocol (HTTP)). This is useful as it is able to detect if an unwanted protocol is attempting to bypass the firewall on an allowed port, or detect if a protocol is being abused in any harmful way. As of 2012, the so-called next-generation firewall (NGFW) is nothing more than the "widen" or "deepen" inspection at application-stack. For example, the existing deep packet inspection functionality of modern firewalls can be extended to include i) Intrusion prevention systems (IPS); ii) User identity integration (by binding user IDs to IP or MAC addresses for "reputation"); and/or iii) Web Application Firewall (WAF).

http://en.wikipedia.org/wiki/Firewall_(computing)#Third_generation:_application_layer
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thpipfhCommented:
I've faced the same problem.

Please block port 25 on firewall.
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chanderpal singh rathoreMicrosoft Exchange EngineerCommented:
HI,

Blocking port 25 is mostly preferred so  
You can block your port by following -----

go to start menu >> control panel >> system and security >> windows firewall >> advance setting >>> inbound rule >> select port 25 >> check out properties and disable it

Good luck
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