Port 25 block aims to minimize spam
In an effort to minimize spam, Duke will block e-mail traffic going directly to the Internet beginning today.
Most junk e-mail is generated by viruses that hijack an infected computer and set it up as independent mail server that bypasses local mail servers and sends out huge volumes of spam.
Many Internet service providers routinely block this traffic on port 25—the virtual pathway that most e-mail traffic follows when it travels from a computer to a server—to minimize spam originating from infected computers on their network. Many computers are infected without their owners' knowledge.
Blocking e-mail going directly to the Internet from Duke's residence network (ResNet) and wireless network helps to prevent Duke computers from inadvertently contributing to cyber attacks like the recent distributed denial of service attacks targeting Facebook and Twitter.
Mail going through Duke's mail servers will not be blocked.
Duke does not scan the content of e-mail messages or attachments and does not block outgoing e-mail based on any judgment about the appropriateness of content.
If you need help with mail configuration, or if you believe legitimate mail is being held up by the block on port 25, please contact the OIT Service Desk for assistance.