Link Sticking; Link Sticking Commands Summary - ZyXEL Communications UAG Series Cli Reference Manual

Chapter 7 Trunks

7.6 Link Sticking

You can have the UAG send each local computer's traffic through a single WAN interface for a
specified period of time. This is useful when a redirect server forwards a user request for a file and
informs the file server that a particular WAN IP address is requesting the file. If the user's
subsequent sessions came from a different WAN IP address, the file server would deny the request.
Here is an example.
Figure 14 Link Sticking
1
WAN1
LAN
LAN user A tries to download a file from server B on the Internet. The UAG uses WAN1 to send the
1
request to server B.
However remote server B is actually a redirect server. So server B sends a file list to LAN user A.
2
The file list lets LAN user A's computer know that the desired file is actually on file server (C). At the
same time, register server B informs file server C that a computer located at the WAN1's IP address
will download a file.
The UAG is using active/active load balancing. So when LAN user A tries to retrieve the file from file
3
server C, the request goes out through WAN2.
File server C finds that the request comes from WAN2's IP address instead of WAN1's IP address
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and rejects the request.
If link sticking had been configured, the UAG would have still used WAN1 to send LAN user A's
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request to file server C and the file server would have given the file to A.

7.7 Link Sticking Commands Summary

The following table lists the ip load-balancing link-sticking commands for link sticking. (The
link sticking commands have the prefix ip load-balancing because they affect the UAG's load
balancing behavior.) You must use the
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3
WAN2
A
configure terminal
2
4
C
command to enter the configuration
B
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