Brocade Virtual ADX Security Guide (Supporting ADX v03.1.00) - Manual (Page 95)

Brocade Virtual ADX Security Guide 83
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Configuring Syn-Proxy
5
Setting the interval time for counting TCP SYN packets
The rate at which Syn-proxy is enabled and disabled is determined by the thresholds set in the ip
tcp syn-proxy on-threshold on-threshold-value off-threshold off-threshold-value command over the
time period specified in the server syn-attack-detection-interval command. This interval is
configured on the Brocade Virtual ADX as shown in the following.
Virtual ADX(config)#server syn-attack-detection-interval 10
Syntax: server syn-attack-detection-interval detection-interval-value
The detection-interval-value variable defines the interval that is used to define the time for
counting TCP SYN packets. The range of settings for this interval is 1 to 10 with each level
representing 100 ms. Consequently, the interval can be from 100 ms to 1 second. If the interval
value is smaller, the reaction time for enabling Syn-proxy is shorter, and the measurement of the
TCP syn-packet arrival rate is less accurate. If the interval value is larger, the reaction time for
enabling syn-proxy is longer, and the measurement of TCP syn-packet arrival rate is more accurate.
The default interval value is 3 (in effect 300ms).
Displaying Syn-Proxy Commands
This section contains the following sections:
• “Displaying TCP Attack Information” on page 83
• “Displaying Server Traffic information” on page 84
• “Displaying SYN Cookie Information” on page 85
Displaying TCP Attack Information
The show server tcp-attack command displays attack information for connection rates counters.
Syntax: show server tcp-attack [debug | fast-path]
Virtual ADX#show server tcp-attack
Connection counters:
Current conn rate = 0 Max conn rate = 1
Attack counters:
Current attack rate = 0 Max attack rate = 0
Client-side counters:
SYN rcvd = 6 SYN-ACK sent = 6
Valid ACKs rcvd = 3 Invalid ACKs rcvd = 33
Client pkt rcvd = 15 Data pkt stored = 3
ACK without data dropp = 0
Destination-side counters:
SYN sent = 3 SYN-ACK rcvd = 3
Duplicate SYN sent = 0 Duplicate SYN-ACK rcvd = 0
Server pkt rcvd = 21 Stored pkt sent = 0