Nortel Networks WEB OS 212777 - Manual (Page 183)

Web OS 10.0 Application Guide
Chapter 7: Filtering n 183
212777-A, February 2002
TCP Rate Limiting Filter Based on Virtual Server IP Address
This example defines a filter that limits clients to 100 TCP connections per second to a specific
destination (VIP 10.10.10.100). Once a client exceeds that limit, the client is not allowed to
make any new TCP connection request to that destination for 40 minutes.
Figure 7-6 shows
how to use this feature to limit client access to a specific destination.
Figure 7-6 Limiting User Access to Server
Configure the following on the switch:
Fastage and slowage are set to 2 seconds and 8 minutes as follows:
time window = timewin x fastage = 1 x 2 seconds = 2 seconds
hold down time = holddur x slowage = 5 x 8 minutes = 40 minutes
max rate = maxcon /time window = 200 connections/2 seconds = 100 connections/second
>> # /cfg/slb/filt 100/ena (Enable the filter)
>> Filter 100 # dip 10.10.10.100/dmask 255.255.255.0
(Specify the virtual server IP address)
>> Filter 100# adv/tcp (Select the advanced filter menu)
>> TCP advanced# tcplim en (Enable TCP rate limiting)
>> TCP advanced# maxconn 20 (Specify the maximum connections)
>> TCP advanced# /cfg/slb/adv (Select the Layer 4 advanced menu)
>> Layer 4 Advanced # timewin 1 (Set the time window for the session)
>> Layer 4 Advanced # holddur 5 (Set the hold duration for the session)
/cfg/slb/adv/fastage 1 (Fastage is set to 2 seconds)
/cfg/slb/adv/slowage 2 (Slowage is set to 8 minutes)
Web Switch
Internet
Real servers Clients
1
2
3
4
Client 1, 2, 3, and 4 are limited
to 100 conn/sec to virtual IP address
Filter 100: 100 conn/sec
VIP: 10.10.10.100
S1
S2