Using Web Proxies

You can configure the Gateway to contact HTTP resources using third party web proxies. Web proxies reside between the client and the Internet.

Web Proxy Configuration

Different proxies may be used for different domains and subdomains. These entries tell the Gateway which proxy to use to contact specific subdomains in specific domains. The proxy configuration specified in the Gateway works as follows:

• Creates a list of domains and subdomains along with the required proxies in the Proxies for Domains and Subdomains field in the Gateway service.

• With the Use Proxy option enabled:

  • The proxies specified in the Proxies for Domains and Subdomains field are used for the specified hosts.

  • To enable direct connections for certain URLs within the domains and subdomains specified in the Proxies for Domains and Subdomains list, specify these URLs in the Do Not Use Web Proxy URLS field.

  With the Use Proxy option disabled:

  • To ensure that proxies are used for certain URLs within the domains and subdomains specified in the Proxies for Domains and Subdomains field, specify these URLs in the Use Webproxy URLs list.

    Although the Use Proxy option is disabled, a proxy is used to connect to the URLs listed under Use Webproxy URLs. The proxies for these URLs are obtained from the Proxies for Domains and Subdomains list.

    The following illustration shows how the web proxy information is resolved based on the proxy configuration in the Gateway service.

    

    In Web Proxy Configuration, if Use Proxy is enabled, and the requested URL is listed in the Do Not Use Webproxy URLs list, the Gateway connects to the destination host directly.

    If Use Proxy is enabled, and the requested URL is not listed in the Do Not Use Webproxy URLs list, the Gateway connects to the destination host through the specified proxy. The proxy, if specified, is looked up in the Proxies for Domains and Subdomains list.

    If Use Proxy is disabled, and the requested URL is listed in the Use Webproxy URLs list, the Gateway connects to the destination host using the proxy information in the Proxies for Domains and Subdomains list.

    If Use Proxy is disabled, and the requested URL is not listed in the Use Webproxy URLs list, the Gateway connects to the destination host directly.

    If none of the above conditions are met, and a direct connection is not possible, the Gateway displays an error saying that connection is not possible.

If you are accessing the URL through the Bookmark channel of the standard Portal Desktop, and none of the above conditions are met, the Gateway sends a redirect to the browser. The browser accesses the URL using its own proxy settings.

Syntax

domainname [web_proxy1:port1]|subdomain1 [web_proxy2:port2]|

Example

sesta.com wp1:8080|red wp2:8080|yellow|* wp3:8080

* is a wild card that matches everything

where,

sesta.com is the domain name and wp1 is the proxy to contact on port 8080.

red is a subdomain and wp2 is the proxy to contact on port 8080.

yellow is a subdomain. Since no proxy is specified, the proxy specified for the domain is used, that is, wp1 on port 8080.

* indicates that for all other subdomains wp3 needs to be used on port 8080.

Port 8080 is used by default if you do not specify a port.

Processing the Web Proxy Information

When a client tries to access a particular URL, the host name in the URL is matched with the entries in the Proxies for Domains and Subdomains list. The entry that matches the longest suffix of the requested host name is considered. For example, suppose that the requested host name is host1.sesta.com. The following searches occur in order until a match is found.

• The Proxies for Domains and Subdomains is scanned for host1.sesta.com. If a matching entry is found, the proxy specified against this entry is used to connect to this host.

• Else, the list is scanned for *.sesta.com. If an entry is found, the corresponding proxy is used.

• Else, the list is searched for sesta.com. If an entry is found, the corresponding proxy is used.

• Else, the list is searched for *.com. If an entry is found, the corresponding proxy is used.

• Else the list is searched for com. If an entry is found, the corresponding proxy is used.

• Else the list is searched for *. If an entry is found, the corresponding proxy is used.

• If no matching centers are found, a direct connection is attempted.

Consider the following entries in the Proxies for Domains and Subdomains list:

com p1| host1 p2 | host2 | * p3
sesta.com p4 | host5 p5 | * p6
florizon.com | host6
abc.sesta.com p8 | host7 p7 | host8 p8 | * p9
host6.florizon.com p10
host9.sesta.com p11
siroe.com | host12 p12 | host13 p13 | host14 | * p14
siroe.com | host15 p15 | host16 | * p16
* p17

The Gateway internally maps these entries into a table as shown in the following table.

Instead of separating the proxy entries in the Proxies for Domains and Subdomains list with the | symbol, you can place individual entries on separate lines in the list. For example, instead of an entry such as:

sesta.com p1 | red p2 | * p3

you can specify this information as:

sesta.com p1
red.sesta.com p2
*.sesta.com p3

This list format makes it easier to track repeated entries or any other ambiguities.

Rewriting Based on the Proxies for Domains and Subdomains List

The entries in the Proxies for Domains and Subdomains list are also used by Rewriter. Rewriter rewrites all URLs whose domains match the domains listed in the Proxies for Domains and Subdomains list.

The * entry in the Proxies for Domains and Subdomains list is not considered for rewriting. For example, entry 24 is not considered.

For information on Rewriter, see Chapter 4, Working with Rewriter .

Default Domain and Subdomain

When the destination host in the URL is not a fully qualified host name, the default domain and subdomain are used to arrive at the fully qualified name.

Assume that the entry in the Default Domains field of the administration console is:

red.sesta.com

You need to have the corresponding entry in the Proxies for Domains and Subdomains list.

In the example above, sesta.com is the default domain and the default subdomain is red.

If the requested URL is host1, this entry is resolved to host1.red.sesta.com using the default domain and subdomain. The Proxies for Domains and Subdomains list is then checked for host1.red.sesta.com.