Data type Range Default value
REG_MULTI_SZ (Blank value | 0 | IP protocol numbers 0


Specifies the TCP ports on which incoming connection requests (SYNs) are accepted on this interface when security filtering is enabled. Security filtering is enabled when the value of EnableSecurityFilters is 1.

Value Meaning
(Blank value -- the entry appears in the registry, but there is no data in the value field.) No SYNs are accepted.
0 (or not in registry) All SYNs are accepted.
Specific IP protocol numbers Only SYNs arriving on these ports are accepted.

Change method

To change the value of this entry, use Network and Dial-up Connections in Control Panel. Right-click Local Area Connection, click Properties, click Internet Protocol (TCP/IP), and then click the Properties button. In the bottom, right corner of the Internet Protocol (TCP/IP) Properties page, click the Advanced button, click the Options tab, click TCP/IP filtering, click Properties and then, just above the TCP Ports box, click Permit Only. This entry is associated with the values added to the TCP Ports list on this page.

Note Image Note

There is no defined or predictable response when the value of this entry includes both a zero and IP protocol numbers. Do not combine these values in this entry.

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