Matching Tcp Flags; Figure 7-11 Tcp Ack Matching Network; Table 7-5 Tcp Flags - Nortel Web OS Switch Software Application Manual

Matching TCP Flags

Web OS supports packet filtering based on any of the following TCP flags.

Table 7-5 TCP Flags

Flag
URG
ACK
PSH
RST
SYN
FIN
Any filter may be set to match against more than one TCP flag at the same time. If there is
more than one flag enabled, the flags are applied with a logical AND operator. For example, by
setting the switch to filter SYN and ACK, the switch filters all SYN-ACK frames.
N
OTE
enabled and cache-disabled filters to the same switch port. For more information, see
Enabled versus Cache-Disabled Filters" on page
Configuring the TCP Flag Filter
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OTE
one or more TCP options are enabled.
Consider the following network:
SMTP
Mail Server

Figure 7-11 TCP ACK Matching Network

212777-A, February 2002
Description
Urgent
Acknowledgement
Push
Reset
Synchronize
Finish
–
TCP flag filters must be cache-disabled. Exercise caution when applying cache-
– By default, all TCP filter options are disabled. TCP flags will not be inspected unless
Internet
178.
Web Switch
1
Router
Web OS 10.0 Application Guide
Inside/
3
Trusted LAN
2
Web Servers:
203.122.186.*
Chapter 7: Filtering
"Cache-
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