3Com 2924-PWR User Guide - Page 78

78 CHAPTER 4: MANAGING DEVICE SECURITY ■ Select from List - Selects a protocol from a list by which packets are matched to the rule. ■ Protocol ID - Adds user-defined protocols by which packets are matched to the rule. Each protocol has a specific protocol number which is unique. The possible field range is 0-255. ■ Source Port - Enables creating an ACL based on a specific protocol. ■ Any - Enables creating an ACL based on any protocol. ■ Destination Port - Defines the destination port that is matched to packets. Enabled only when TCP or UDP are selected in the Protocol list. ■ Any - Enables creating an ACL Based on any protocol. ■ TCP Flags - If checked, enables configuration of TCP flags matched to the packet. The possible fields are: ■ Urg - Urgent pointer field significant. The urgent pointer points to the sequence number of the octet following the urgent data. ■ Ack - Acknowledgement field significant. The acknowledgement field is the byte number of the next byte that the sender expects to receive from the receiver. ■ Psh - Push (send) the data as soon as possible, without buffering. This is used for interactive traffic. ■ Rst - Reset the connection. This invalidates the sequence numbers and aborts the session between the sender and receiver. ■ Syn - Synchronize Initial Sequence Numbers (ISNs). This is used to initialize a new connection. ■ Fin - Finish. This indicates there is no more data from the sender. This marks a normal closing of the session between the sender and receiver. For each TCP flag, the possible field values are: ■ Set - Enables the TCP flag. ■ Unset - Disables the TCP flag. ■ Don't Care - Does not check the packet's TCP flag.