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DePennifying URLs: How To Remove PennKey Elements from URLs

This guide gives guidance on removing PennKey-authentication artifacts from URLs for online resources licensed by the Penn Libraries.

Why this page?

The Penn Libraries license electronic resources for use by currently affiliated University of Pennsylvania students, faculty, and staff.

Most of our licensed electronic resources use IP-range authentication : we give our vendors the IP ranges used by the University of Pennsylvania, and they configure their databases to provide access to any IP addresses within those ranges. For on-campus readers, access is almost always seamless.* That is, you in your dorm, classroom, or library will see the licensed database, ebook, ejournal article, or videostream, no problems.

For off-campus readers, the Penn Libraries use EZproxy authentication to move you into Penn's IP ranges. EZproxy prompts off-campus readers for their PennKeys. After a successful login, EZproxy will often modify the URL for the web page you want to read, so that you can see that it's an electronic resource licensed by the Penn Libraries. These "Pennified" URLs work for Penn readers and they contain all the elements -- in modified form -- needed for a non-Penn reader to get at the web page you want them to read ... but you can make the lives of non-Penn readers easier by dePennifying URLs as needed.

* Some vendors require that we use EZproxy authentication for on-campus readers too.

What to look for, what to change

Pennified URLs generally take two forms:

  • Proxy prepend URL :
  • Base URL proxy postpend :

Editing a proxy prepend URL -- this is easy!

Pennified version:

DePennified version:

See that? Delete the proxy prepend!

Editing a base URL proxy postpend -- this requires some work.

Pennified version:

DePennified version:

What happened here? First, I deleted the proxy postpend from the base URL : Second, in the base URL, I changed all the hyphens (-) to periods (.). WATCH OUT! Make these edits only in the base URL, not in the trailing parts of the URL.


What can go wrong?

Ha! Better to ask, What can't go wrong?

Some URLs include arguments. These often appear in the URL following a question mark (?). Some of these arguments may be necessary for the URL to work, pointing precisely to what you want to read -- you want to keep these. Some arguments are breadcrumbs, used to provide a search history -- you probably don't want to keep these. And some, I don't know what they do, they can be session- or time-sensitive -- and I really don't want to keep these but I might have to if the URL won't work with out them. More important, though : These are NOT EZproxy artifacts, they are the result of how the vendor's database works.

Example with unnecessary argument:


What happened here? First, I deleted the base URL proxy postpend. Second, I changed the base URL's hyphens to periods. Third, I deleted the question mark and everything following it. Fourth, I tested the URLhoping to see if it would work properly (if I am on campus) or return a login prompt or turnaway message (if I am off campus). If it returned an error message, then I would restore the URL argument and move on.

And some proxied URLs just cannot be hacked. For those, try to provide as complete bibliographic information as you can, and provide the dePennified base URL for the electronic resource. This will help your readers to retrace your steps ... if they had access to the electronic resource, You may need to include a cautionary note, such as "(subscription required)".

Anything else?

Now that you know how to dePennify the URL for an electronic resource licensed by the Penn Libraries, you have the skills to Pennify a URL to see if the Penn Libraries have licensed the electronic resource using that URL.

Example. This ebook URL:

can be Pennified with the proxy prepend URL:

and can be Pennified with the base URL proxy postpend (and changing base URL periods to hyphens):

Or you could install Lean Library and the EZproxy bookmarklet, the Penn Libraries web browser extensions that automate the Pennification for you.

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