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Find out which ports are blocked by XFINITY and Comcast services, and why.
Reason for block
Port 25 is unsecured, and Botnet spammers can use it to send spam. This does not affect XFINITY Connect usage. We recommend configuring your email program to use port 465.
UDP Port 68, which is used to obtain dynamic Internet Protocol (IP) address information from our dynamic host configuration protocol (DHCP) server, is vulnerable to malicious hacks.
NetBios services allow file sharing over networks. When improperly configured, ports 135-139 can expose critical system files or give full file system access (run, delete, copy) to any malicious intruder connected to the network.
Port 445 is vulnerable to attacks, exploits and malware such as the Sasser and Nimda worms.
Port 520 is vulnerable to malicious route updates, which provides several attack possibilities.
Port 1080 is vulnerable to, among others, viruses, worms and DoS attacks.
Description for Determine your blocked IP address
Learn how to block ports through your Comcast Network.
Learn more about why email port 25 is no longer supported.
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