CTAN Comprehensive TeX Archive Network

Help on CTAN

How can I select a certain mirror to download a package?

Most of the time the automatic mirrors selection of CTAN provides satisfactory results. CTAN keeps track of a number of mirrors. These mirrors are monitored for availability. Mirrors which are not reachable for some time are considered inactive and not taken into account for content delivery. The content delivery is triggered by URLs of the form

http://mirrors.ctan.org/path

As soon as such an URL is requested, CTAN selects a mirror and redirects your request to this server. This mechanism dates back when bandwidth across continents was restricted and slow. It also distributes the traffic to many servers. This still serves well today. For this purpose CTAN has a mechanism which tries to guess the geo location of the requester. Based in this location a server in the same region is selected.

This mechanism serves well most of the time. Unfortunately there are rare situation when the result needs to be overwritten.

  • Packages usually need a short time like a day to be replicated to all mirrors. Thus if you land at a mirror with an slightly outdated version. You may want to try another one.
  • Mirrors are monitored. This does not give availability status by the second. A mirror might be offline shortly and you need to use another one.
  • Mirrors might by blacklisted and unreachable from your current location. Thus you need another one.

Retry First

The easiest way out of this problem is to retry the link again. Since the mirror is chosen randomly in the region the chances are good that you land on another server.

Navigate Manually

If the retry does not work you can use a more complicated procedure described here.

  1. Suppose you find a URL on CTAN of the form for mirrors depicted above. You have to remember the path contained in it.
  2. Navigate to the page CTAN: Sites which is also contained in the menu on each page.
  3. Select the mirror of your choice and click on the http or ftp link given. You are redirected to the root directory of tex-archive on the selected server.
  4. Now you need the path contained in the original URL. Extend the URL in your browser with this path and request the respective page. If everything goes right you are at the same target which you would get via the automatic mirror selection.
  5. You can use the page The Status of the CTAN Mirrors and look-up the selected mirror if your connection fails. There you might get indications about longer lasting problems of the server.
Guest Book Sitemap Contact Contact Author