Microsoft Internet Security and
Acceleration Server 2000
ISA Server can also make internal servers securely accessible to
external clients. You use ISA Server to create a publishing policy
to securely publish your internal servers. The publishing policy,
which consists of Internet protocol (IP) packet filters, Web
publishing rules, or server publishing rules, together with the
routing rules, determine how internal servers are published.
You can use one of the following ISA Server rules to publish
Web publishing rules to publish Web server content.
Server publishing rules to publish content on all other
servers located on the internal network.
IP packet filters to publish content on servers on a
perimeter network (also known as a screened
When ISA Server processes a request from an external client, it
checks IP packet filters, publishing rules, and routing rules to
determine if the request is allowed and which internal server
should service the request.
For an incoming Web request, rules are processed in the
IP packet filters. If packet filtering is enabled, then if an
IP packet filter specifically denies the request, the request is
Web publishing rules. If a Web publishing rules specifically
denies the request, then the request is denied.
Routing rules. If a routing rule specifies that the requests be
routed to a specific upstream server or an alternate hosted site,
then the specified server handles the request. If a routing rule
specifies that the requests be routed to the specified server, then
the internal Web server returns the object.