Proxy Servers: Basics and Resources

A proxy server is a service that provides authentication and mediation between database or publisher websites and the end user by routing Internet traffic through its system.

Why learn about proxy servers?

A proxy server is a service that libraries use to authenticate their users to provide access to many online databases and publisher websites.  Using a proxy service allows library resource vendors to authenticate users from a single point-of-access regardless of where they are located, on-campus or from their home computer.

The Basics

For our examples, we’ll use the popular EZproxy product from OCLC.


To avoid having to provide users with an individual or institutional login and password, most database and publisher websites authenticate users by IP address.  Sometimes vendors will limit access to a range of IP addresses—on a single campus, for example.  But for users outside of the physical campus, you must provide a known IP address (or set of IP addresses). This is accomplished by routing users through a proxy server so that the access requests come from its IP address(es) which are recognized by the vendor.  The content is then returned to the proxy server and routed back to the original user.

EZproxy process

Because libraries can’t let everyone access their resources via EZproxy, they must authenticate their users before access.  EZproxy allows user login itself, but EZproxy also provides a method of authentication using your institution’s single sign-on (SSO) server.

Resource Access

EZproxy is accessed using an HTTP request.  To access a website via EZproxy, you must prepend the EZproxy server URL to the database or publisher’s website address.  A typical EZproxy URL looks like this:

To this proxy URL, we add the URL for the website we wish to access through EZproxy. For example:

The above URL is referred to as a “pre-proxy” link.  Once a website is accessed via EZproxy, the address changes to a “post-proxy” URL.  For example:

As you perform a search or click on links on a database or publisher site, you are submitting your requests to your EZproxy server which passes them on to the original website.  Data is returned to the EZproxy server which sends it back to your browser.  That is why the post-proxy URL ends with (ignoring the path).

You might notice some post-proxy URLs use hyphens instead of dots between parts of the original website’s address.

The short explanation is that the EZproxy server uses a wildcard security (SSL) certificate for * which allows one subdomain before the EZproxy server domain (  The hyphens “trick” the server into seeing the original website as a single subdomain. This is done only for original websites that use HTTPS.

EZproxy Configuration

EZproxy has many settings that are configured during initial installation (using hyphens with HTTPS, for example).  You also set the maximum number of virtual hosts (typically from 5,000 to 20,000).

For each resource you access through EZproxy, you must configure it separately in a block of code called a stanza.  In the stanza for a database or publisher website you must specify at the minimum a Title (T) and starting URL (U).  Other basic stanza directives are Host (H), HostJavaScript (HJ), Domain (D), and DomainJavaScript (DJ).  Below is a basic database stanza:

Title SPIE Digital Library

The Title directive is used to identify the resource (and is used for the link text on the default EZproxy list page).  The URL is used to match the EZproxy request link with the appropriate stanza to apply.  Once accessed, any further links on the resource site will be compared to any D or DJ lines and if there is a match, will be proxied and given access (including any JavaScript if a DJ line is encountered).

If a database or publisher website includes multiple domains or subdomains or uses both HTTP and HTTPS, you need to add Host (H) or HostJavaScript (HJ) directives to account for them.  More advanced directives are used to manage website cookies, set domains that should never be proxied, find and replace HTML code, and many others.  OCLC publishes an EZproxy Reference Manual to list these directives.

Here is a more advanced database stanza:

Option DomainCookieOnly
Title Engineering Village
Option Cookie

OCLC publishes a list of recommended database stanzas for many of the most popular databases.  Of course, websites are frequently updated and these changes often require revised or completely new stanzas.  These stanzas are found in the config.txt file.


Here are some resources to learn more about EZproxy.


Library Service Status Pages

Online library services play a vital part in providing access to library resources and services.  Thus, it is very useful for library staff to know the status of these third-party services.  Downtime is rare, but when staff and users need to know the availability of online services, having a library service status page can be extremely helpful.  Fortunately, library vendors know this and increasingly are providing access to websites for displaying current service status and notices of planned interruptions.

Here is a list of the known major library service status pages:


bepress Current Statusbepress supports institutional repositories with Digital Commons, SelectedWorks, Expert Gallery Suite, and ExpressO online manuscript delivery service.  Their website has a Current Status page that covers all of these services including status details, scheduled maintenance, and recent product updates.

Access the bepress Current Status page.


EBSCO Help Alerts

On its EBSCO Help website, the company provides News and Alerts for its wide range of databases and EBSCO Discovery Service (EDS).  You can enter your email address to subscribe to alerts, as well.

Access the EBSCO Help Alerts page.

Ex Libris

Ex Libris System Status

With the merger of Ex Libris and ProQuest, Ex Libris took over the support of all library systems and discovery services.  The company has created a unified system status page for Alma, Summon, Serials Solutions 360 Link, Intota, Primo, SFX, and more.

Access the Ex Libris System Status page.


OCLC System AlertsFrom the OCLC Support & Training website, you can access OCLC System Alerts.  This blog-like site reports current and past maintenance and issues for services including Connexion, hosted EZproxy, WorldCat, and WorldShare products.

Access the OCLC System Alerts page.


SirsiDynix Status

SirsiDynix is a major library vendor with cloud-based systems such as their BLUEcloud services.  The company’s status page contains notifications of scheduled maintenance and outages by region.

Access the SirsiDynix Status page.


Springshare Systems Status Dashboard
Source: Springshare

Springshare understands the importance of providing status information for library resources and services to library users.  That’s why they created the Systems Status Dashboard in LibAnswers that allows your library to set up and display the status of your website, LibGuides, local resources, and databases.  You can alert users to any planned system maintenance and explain unexpected downtime.  For any LibAnswers site that has enabled the public status dashboard, you can view it by adding /systems after their LibAnswers URL.  Some examples are Manchester Metropolitan University, the University of Maryland Libraries, and Georgia College.

Read more about the Springshare Systems Status Dashboard.

TwitterIn addition to bookmarking the above sites, follow your important library vendors on Twitter.  That is where they will often post the first announcements of issues and further status reports.

The Virtual International Authority File (VIAF)

VIAF Authority Record for Harper Lee

The authority file goes global.

It was probably inevitable that there would be an attempt to create a global authority file for library bibliographic data.  Any worldwide authority file would need the support of major national libraries and library organizations.  We now have the first viable candidate.

VIAFThe Virtual International Authority File (VIAF) is not a new service, but one that has become more prominent in recent times due to the direction of OCLC (starting in 2012) and the rise of linked data. It began as a joint project of the Library of Congress and the German National Library, then the National Library of France and OCLC, but now has a long list of contributors.

From OCLC, the VIAF service has these characteristics:

  • A collaborative effort between national libraries and organizations contributing name authority files, furthering access to information
  • All authority data for a given entity is linked together into a “super” authority record
  • A convenient way for the library community and other agencies to repurpose bibliographic data produced by libraries serving different language communities

The VIAF combines the national authority files—which contain data such as names of authors and companies, conferences, places, and subject headings in their native languages—into a single international name authority service.

There are several benefits of a global name authority file (or service). Obviously, there is the fundamental benefit of providing uniform names for indexing and searching.  With a global authority file, the connecting application, such as a discovery service, can retrieve and display names based on the language of the application’s user interface—and can switch on-the-fly.  It enables the generation of “see” and “see also” links across languages.  The VIAF allows developers to search and access the authority data using an API.

As mentioned at the beginning, the VIAF is one source which can be accessed via a linked data URI.  Here’s an example:

creator: {
@id: “”,
label: “Wodehouse, P. G. (Pelham Grenville), 1881-1975”,
sameAs: “|n78089036”

The above operation translates a Library of Congress control number for an author to the related VIAF record.

You can search the VIAF at

View a typical authority record at

VIAF authority Record Map for P. G. Wodehouse

Consolidation of the Library Vendors


With two recent announcements of mergers of well-known library vendors—ProQuest acquired Ex Libris and Bibliotheca bought 3M Library Systems—the number of independent library vendors is shrinking.

ProQuest is now a provider of research databases (ProQuest Central and others), ebooks (ebrary, EBL, and MyiLibrary), discovery tools (Summon and now Primo), link resolvers (Serials Solutions and now SFX), library management system (Alma and Intota), and print books (with the recent purchase of Coutts).

EBSCO is the next largest vendor in this shrinking field.  EBSCO offers research databases (EBSCOhost), ebooks (EBSCO eBooks and Audiobooks), a discovery tool (EBSCO Discovery Service), a link resolver (LinkSource), and print books (YBP Library Services).  EBSCO does not offer an ILS or LMS and one has to wonder if the company will go looking to acquire one.

OCLC is the third major competitor in the library services arena. OCLC does not provide content like ProQuest and EBSCO.  However, they offer a discovery tool (WorldCat) and a modern library management system (WorldShare Management Services).  OCLC also offers popular services such as a proxy service (EZproxy), interlibrary loan service (ILLiad), digital collection management tool (CONTENTdm), and a virtual reference system (QuestionPoint).

If your library is looking for a comprehensive library management / discovery service / link resolver solution, you now have three vendors.

Further Reading

American LibrariesProQuest to Acquire Ex Libris

Globes: ProQuest to buy Israeli co Ex Libris for $500m

Ithaka S+R: What Are the Larger Implications of ProQuest’s Acquisition of Ex Libris?