The use of web accelerators can be a great convenience. As accelerator use is becoming more and more prevalent it is necessary for campus library staff to be aware of the potential problems caused by their use and to communicate this information to their faculty and students.

Web accelerators are applications that use various techniques to make web pages load faster or to download links, images, or files more quickly.  Google Web Accelerator and the Firefox plugin “DownThemAll” are some commonly used products.

The two main problems caused by the use of web accelerators:

  • Users cannot access licensed content from a valid UC IP address.
  • Triggering of vendor “excessive downloading” thresholds which can result in the user’s IP address being blocked by the vendor.

This second situation can be especially problematic if the user is accessing the vendor’s content via a campus proxy server or VPN.  In cases like this, the actions of one person can shut down access to a vendor’s resources for all users of a campus proxy server or VPN until the problem is resolved and the vendor removes the IP block!

Examples from the CDL Helpline files:

1.  Google Web Accelerator & JSTOR

A user accessing licensed content from on-campus was blocked from viewing JSTOR’s online content because JSTOR did not recognize the user’s IP address as a valid UC campus IP address.  JSTOR displayed the following message, “We’re sorry.  You do not have access to JSTOR from your current location.

The user was blocked because Google Web Accelerator sends the user’s page requests through Google machines dedicated to handling Google Web Accelerator traffic, thus, the request comes from a Google IP address, not the UC user’s IP address.  JSTOR Technical Services advised the user to add JSTOR’s domain ( to the “Don’t Accelerate These Sites” text area in Google’s Web Accelerator Preferences section; see for more information.

2.  Access to Ejournal Site Blocked by the Vendor

With web accelerators it becomes very easy to trigger “breach of contract” issues.  Recently, CDL was notified by a vendor that a user’s IP had been blocked because of “excessive downloading”, in this case, the downloading of an entire issue of a specific online journal.  IP blocks can be triggered when an excessive number of files are downloaded from a single IP address within the vendor’s pre-determined period of time (whether or not the files appear in the same online journal issue).

What you should know and do:

  • Most of UC’s access to licensed electronic resources is controlled by IP addresses.
  • If a patron is using the campus proxy server or VPN service and initiates a breech, this can result in a lockout to that vendor’s site for all proxy or VPN users.
  • Please communicate this information to the students and faculty at your campus, and troubleshoot user problems if they arise.