Basically, caching web proxies provides administrators
with a good way to conserve precious bandwidth for critical network services without
having to take draconian measures with regard to users??™ ability to access the web. Often
users request the same resources and content from the web. Caching web proxies will
download and save this content while retrieving it for the client that requested it. When
subsequent requests for this same content are made, the content can be returned by
the proxy without having to download it from the Internet again, thus conserving
bandwidth. Of course, web content does not remain static so it is important to tune
caching rules so that the proxy eventually identifi es its local copy of the content as
stale, and again retrieves an updated copy from the Internet.
Add-ins
The Add-ins node in the ISA Server Management Console allows administrators to
access application-level fi lters. These are separated into two groups and displayed on
two tabs in the interface, and the distinction between these is a bit confusing at fi rst.
The fi rst tab shows Application Filters, which are dynamic link libraries (DLL) that
proxy a number of different traffi c protocols including:
?– Domain Name Service (DNS)
?– File Transfer Protocol (FTP)
?– Remote Procedure Call (RPC)
?– Point-to-Point Tunneling Protocol (PPTP)
?– Simple Mail Transfer Protocol (SMTP)
There are a few other application fi lters provided as well, including one labeled
Web Proxy Filter.
Pages:
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393