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Migrate to Proxy by Hostname

By default, EZproxy uses a Proxy by Port configuration, which operates by mapping hostname/port number combinations used by web servers into a port number on your EZproxy server. The Proxy by Hostname configuration allows EZproxy to map hostname/port number configurations to unique hostnames that refer back to the EZproxy server.

OCLC will end support for EZproxy’s proxy by port option on 30 September 2020, due to its incompatibility with many popular e-resource websites.

If you are currently running proxy by port, you may continue to do so for the time being. After 30 September 2020, you will need to enable Proxy by Hostname in order to receive support from OCLC. Proxy by hostname will help ensure seamless access for your library’s e-resource subscriptions. For more information, please see migrating to Proxy by Hostname or contact OCLC Support. 

This change does not touch existing config.txt files, so any existing sites using proxy by port will be unaffected by this change.  For more information please review our proxy by port and hostname comparison page.  

For example, by default, could be mapped to With proxy by hostname, maps to (the URL generated after a user clicks on the starting point URL

The key advantage to the proxy by hostname configuration is that this allows EZproxy to operate on a single port. This eases resource requirements on your server and simplifies both local and remote firewall configuration issues.

Proxy by host name configuration requires and SSL certificate that is specific to the name of EZproxy.


Proxy by hostname in config.txt

The config.txt file generated and stored in your EZproxy directory when you first download and install the software contains the following, commented out configuration.

##  EZproxy must be set to Proxy-by-port or to Proxy-by-hostname:
##  see
##                             AND
# Option ProxyByHostname
##  By default, EZproxy listens on port 2048. You can specify a different port here
# LoginPort 80

If you are configuring Proxy by Hostname in a newly installed config.txt, un-comment directive lines as necessary when stepping through the configuration instructions below. Additional directives can be included.

Proxy by hostname configuration

  1. First, your DNS administrator must create two entries for your server. If your EZproxy server will run on, and if it will operate under the name, then the entries would be:   IN A
    * IN A

    Both of these entries should be made as A records, not CNAME records.

    If you manage DNS on Windows servers, see Proxy By Hostname Windows DNS Configuration for the steps required to create these entries.

  2. Verify your wildcard DNS entry by browsing to Check DNS and entering the name of your EZproxy server and selecting the wildcard check.

     Caution: Do not proceed until your wildcard entry passes this test.

  3. Make a backup copy of your config.txt file.
  4. Proxy by hostname is activated by editing config.txt and adding this line anywhere in the file:
    Option ProxyByHostname

    If you are configuring EZproxy with a new config.txt file, un-comment this line. It is located towards the top of the file in the block noted above.

  5. If you are not running another web server on the EZproxy server and would like to have EZproxy operate on the standard web server port of 80, edit config.txt and add this line:
    LoginPort 80

    If you are configuring EZproxy with a new config.txt file, un-comment this line. It is located towards the top of the file in the block noted above.

    Running EZproxy as Root on Linux

    If you use "LoginPort 80" on a Linux system, EZproxy must be started as root. If you do this, OCLC strongly recommends that you add the RunAs directive statement to your config.txt so that EZproxy does not run as root after startup.

    Using Multiple LoginPorts

    LoginPort can appear in config.txt more than once. The first appearance defines the "primary location" for logins. Other lines can indicate alternate ports. where EZproxy should listen.

    For example, if your old URLs reference port 2048 as the main login port, you may have many old URLs that refer to this port. In your server, you could use the following to allow the old URLs to continue to function:

    LoginPort 80
    LoginPort 2048
  6. Restart EZproxy for your changes to take effect.

Optional: Running two web servers on port 80

If you already run a web server on the same server that hosts EZproxy, but you want to use port 80 to alleviate firewall issues, this is possible, although it requires that you assign an additional TCP/IP address to the EZproxy server. For more information on how to add a second IP address see Linux or Windows.

Note: EZproxy is no longer supported on a server also running IIS. See: Add a second IP address to an existing network adapter on Windows.

If you configure EZproxy with a new IP address, you will need to complete the first two steps of this document for the new IP address before you can reconfigure EZproxy to use its new name.

If you want to keep old URLs that point to the old name:2048 working, you can use entries in config.txt similar to this:

LoginPort 80
Interface ANY
LoginPort 2048

This sample configuration tells EZproxy that it should identify itself as, but it should also listen for requests on port 2048 for any other name that points to this server.

After making these changes, restart EZproxy to begin testing. EZproxy will use only a single port, but you will see the host names change as you access different sites.

If you are able to login, but then start seeing "Page not found" errors, your wildcard DNS entry may not be correct. In this instance, you should rename config.txt to another name, restore config.txt from the backup you made in step 3, restart EZproxy, and contact OCLC Support  for additional assistance.

Using CGI authentication?

If you are using CGI authentication and you change the port on which EZproxy listens (e.g. 2048 to 80), you must adjust your CGI script to reference the new port as well (e.g. $ezpport=2048; to $ezpport=80;). Failing to adjust your script will lead to a strange, confusing error message and a total disabling of login processing.

Starting point URLs

In the default proxy by port configuration, starting point URLs typically take this form:

In proxy by hostname, starting point URLs remain in this basic form. The only change that may occur in a switch to proxy by hostname occurs if you choose to move from port 2048 to port 80, in which case you can drop the port number, which would change the general form to:

In all instances, you will still have a URL composed of your EZproxy hostname, perhaps a port, then /login?url= followed by the target URL. See Starting point URL for more information.

All references in the preceeding instructions to hostnames like are used solely by EZproxy as it proxies users, just as EZproxy internally uses forms like to present remote hosts in proxy by port. These are not things that you will use in URLs that you setup for EZproxy.

Release old ports

If you are converting to proxy by hostname from proxy by port, EZproxy will continue to listen on the old ports to allow bookmarks to the old ports to work. Once you have tested and confirmed that everything is working correctly, you can direct EZproxy to release the old ports. To do this:

  1.  Log in to your EZproxy administration page.
  2. Click View server status.
  3. On the Server Status page, click Host Maintenance.
  4. At the bottom of the screen, you will find an option to direct EZproxy to release the old ports. If you do not find the host maintenance option, you will need to update to a newer release of EZproxy to release these ports, or these ports may have already been released.
  5. Restart EZproxy for the changes to take effect.