Block Lists

This content has moved. You can now find ISO Block Lists in SocReg,

The Information Security Office (ISO) maintains a list of hosts that are blocked from the campus network. IP and MAC blocks may be viewed by anyone with a valid CalNet login; however CalNet UIDs blocked from the eduroam network and/or VPN are only available to specific IT support staff.

Some ports are blocked by default on the campus networks: 137/tcp, 138/tcp, 139/tcp, 445/tcp, 69/udp

You can track open ISO security issues related to each blocked host.

Access to Blocked UID list

If you provide technical support to the campus and need access to the Block UID list, have your supervisor email a request to They will need to include your department name, the reason you need access, and their approval. 

Block Inquiry

If you believe your account or computer has been blocked because of a security alert please look for an email from: 'Security Operations via RT <>' and respond to that email.

Please include the ISO ticket number [ISP #11xxxxx], with brackets in the subject line.

Block Resolution

Once all security issues have been resolved, email and include the following in the Subject line of your message:

  • ISO security notice tracking number including the enclosing brackets from the original security notice you received from ISP

  • IP address or Mac Address that is currently blocked


  • Subject: Block Removal Request - [INC#1000000]

  • Subject: Block Removal Request - 00:11:22:33:44:55 [ISP #1000000]

Please see Respond to a Security Notice for how to resolve issues.