Cisco Cisco Web Security Appliance S160 Guía Del Usuario
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Cisco IronPort AsyncOS 7.5 for Web User Guide
Chapter 10 Working with External Proxies
Adding External Proxy Information
Figure 10-1
Routing Policies
When you define multiple external proxies in a proxy group, the Web Proxy can use load balancing
techniques to distribute requests to different proxies defined in the group. You can choose the following
load balancing techniques:
techniques to distribute requests to different proxies defined in the group. You can choose the following
load balancing techniques:
•
None (failover). The Web Proxy directs transactions to one external proxy in the group. It tries to
connect to the proxies in the order they are listed. If one proxy cannot be reached, the Web Proxy
attempts to connect to the next one in the list.
connect to the proxies in the order they are listed. If one proxy cannot be reached, the Web Proxy
attempts to connect to the next one in the list.
•
Fewest connections. The Web Proxy keeps track of how many active requests are with the different
proxies in the group and it directs a transaction to the proxy currently servicing the fewest number
of connections.
proxies in the group and it directs a transaction to the proxy currently servicing the fewest number
of connections.
•
Hash based. The Web Proxy uses a hash function to distribute requests to the proxies in the group.
The hash function uses the proxy ID and URL as inputs so that requests for the same URL are always
directed to the same external proxy.
The hash function uses the proxy ID and URL as inputs so that requests for the same URL are always
directed to the same external proxy.
•
Least recently used. The Web Proxy directs a transaction to the proxy that least recently received
a transaction if all proxies are currently active. This setting is similar to round robin except the Web
Proxy also takes into account transactions a proxy has received by being a member in a different
proxy group. That is, if a proxy is listed in multiple proxy groups, the “least recently used” option
is less likely to overburden that proxy.
a transaction if all proxies are currently active. This setting is similar to round robin except the Web
Proxy also takes into account transactions a proxy has received by being a member in a different
proxy group. That is, if a proxy is listed in multiple proxy groups, the “least recently used” option
is less likely to overburden that proxy.
•
Round robin. The Web Proxy cycles transactions equally among all proxies in the group in the
listed order.
listed order.
For information about creating Routing Policies, see
.
Note
If your network contains an upstream proxy that does not support FTP connections, then you must create
a Routing Policy that applies to all Identities and to just FTP requests. Configure that Routing Policy to
directly connect to FTP servers or to connect to a proxy group whose proxies all support FTP
connections.
a Routing Policy that applies to all Identities and to just FTP requests. Configure that Routing Policy to
directly connect to FTP servers or to connect to a proxy group whose proxies all support FTP
connections.
Adding External Proxy Information
To define external proxy information, you create a proxy group. A proxy group is an object that defines
a list of proxies and their connection information and the load balancing technique to use when
distributing requests to proxies in the group. You can create multiple proxy groups and can define
multiple proxies within a group.
a list of proxies and their connection information and the load balancing technique to use when
distributing requests to proxies in the group. You can create multiple proxy groups and can define
multiple proxies within a group.
AsyncOS for Web allows you to enter the same proxy server information multiple times into the same
proxy group. You might want to include the same proxy server multiple times to allow unequal load
distribution among the proxies in the proxy group.
proxy group. You might want to include the same proxy server multiple times to allow unequal load
distribution among the proxies in the proxy group.