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HTTP is the application-layer protocol that most web pages are transferred with. HTTP keep-alive connections can be re-used for multiple requests, as opposed to non-keep-alive connections, which are limited to one request. Using keep-alive connections improves performance. If a proxy server is not configured, the total number of HTTP keep-alive connections the application can make to each site is limited by this preference. If more connections are needed, they are queued until a connection "slot" is available.

Possible values and their effects

This preference takes values between 1 and 255 inclusive, directly corresponding to the maximum number of HTTP keep-alive connections the application can have open at once to a single server. (Default: 2. Firefox 3: 6)


Recommended settings

If you are not using a proxy and experience problems not being able to download multiple files, you can raise this value. It is, however, considered poor etiquette to make too many connections to a server and may lead to you being banned from that server. Anything above 10 is excessive.

First checked in

2001-09-04 by Darin Fisher

Has an effect in

  • Netscape (all versions since 7.0)
  • Mozilla Suite (all versions since 0.9.4)
  • Mozilla Phoenix (all versions)
  • Mozilla Firebird (all versions)
  • Mozilla Firefox (all versions)
  • SeaMonkey (all versions)
  • Camino (all versions)
  • Minimo (all versions)

Related bugs

Related preferences

External links