Handbook

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Table 15 Well-known application ports
Number
TCP/UDP
Application
Number
TCP/UDP
Application
Number
TCP/UDP
Application
69
tftp
161
snmp
1985
hsrp
70
gopher
162
snmptrap
Table 16 Well-krown TCP flag values
Flag
Value
URG
0x0020
ACK
0x0010
PSH
0x0008
RST
0x0004
SYN
0x0002
FIN
0x0001
Packet Format
Ethernet format (EthernetⅡ, SNAP, LLC)
Ethernet tagging format
Egress port packets
Note that the egress port ACL will not match a broadcast, multicast, unknown unicast, or Layer 3
packet. The egress port ACL will not match packets if the destination port is a trunk member.
Summary of ACL actions
Actions determine how the traffic is treated. The switch QoS actions include the following:
Pass or Drop
Re-mark a new DiffServ Code Point (DSCP)
Re-mark the 802.1p field
Set the COS queue
Understanding ACL precedence
Each ACL has a unique precedence level, based on its number. When an incoming packet matches the
highest precedence ACL, the ACL‘s configured action takes place. The other assigned ACLs also are
considered, in order of precedence.
ACLs are divided into Precedence Groups, as shown in the following table.
Precedence Group
ACLs
Precedence Level
Precedence Group 1
ACL 1 – ACL 128
Low
Precedence Group 2
ACL 129– ACL 256
Precedence Group 3
ACL 257 – ACL 384
High
NOTE: Precedence Groups are not related to ACL Groups.
Each Precedence Group has its own precedence level, such that Precedence Group 2 has a higher
precedence level than Precedence Group 1. Within each Precedence Group, higher-numbered ACLs
receive higher precedence, so that the lowest-numbered ACL has the lowest precedence level, and the
highest-numbered ACL has the highest precedence level.