# Apache Tomcat 4

# Connectors Overview

Introduction

> There are two different types of connectors. Connectors that allow browsers to connect directly to the Tomcat and connectors that do it through a Web Server.

> The connectors allowing direct connections are distributed as jar files with the Tomcat binary releases.

> The connectors used with a Web Server are made of 2 components. One written in Java and the other written in C. The Java part is included, as a jar file , with the Tomcat binary releases. The C part is released separately and may be obtained from the Tomcat Connectors Downloads.

> The total number of different operating systems and web servers is sufficiently large that it is not practical to provide binaries downloads for every combination. Binaries are provided for most of the popular combinations and if the one you need is not available do not hesitate to ask for it on the tomcat-user mailing list but please be patient and accept you may have to build it yourself with the help of the mailing list.

> The source code for the Tomcat Connectors is available from the SVN repository (Tomcat SVN structure) or as a bundle (that includes both the Java and the C components) from the Tomcat Connectors Downloads.

Tomcat connectors

> The following table lists most of the existing Tomcat connectors.

> HTTP Connectors for Tomcat 4.x
> Client | Protocol | Tomcat className | Notes
> --- | --- | --- | ---
> Modern browser | HTTP/1.1 | org.apache.coyote.tomcat4.CoyoteConnector | Current practice See Coyote HTTP/1.1
> Modern browser | HTTP/1.1 | org.apache.catalina.connector.http.HttpConnector | Deprecated See HTTP/1.1
> Ancient browser | HTTP/1.0 | org.apache.catalina.connector.http10.HttpConnector | Deprecated See HTTP/1.1
> Web Server Connectors
> Web Server Side | Protocol | Tomcat Side | Notes
> JK | AJP/1.3 | CoyoteConnector with JkCoyoteHandler | Current mod_jk supports load balancing. Enabled by default in 4.1; works in 4.0. See JK and Coyote JK.
> mod_proxy with AJP enabled | AJP/1.3 | CoyoteConnector with JkCoyoteHandler | Current Available for Apache httpd 2.x and included by default with 2.2. See mod_proxy_ajp and Coyote JK
> mod_jserv | AJP/1.2 | Ajp11 | Obsolete Read more at JServ
> JK2 | AJP/1.3 | CoyoteConnector with JkCoyoteHandler | Deprecated Enabled by default in 4.1. mod_jk2 supports in-process JVM and load balancing. See JK2
> JK or JK2 | AJP/1.3 | org.apache.ajp.tomcat4.Ajp13Connector | Deprecated See AJP/1.3
> mod_webapp | WARP/1.0 | WarpConnector | Deprecated Not for Win32; no in-process nor load balancing; works in 4.x. Uses APR. Supported Apache-2.0 and Apache-1.3). See Webapp

Why a Tomcat connector with a native Web Server?

> A Web Server can host different applications written using PERL, PHP, C or any other language. If one application is written in Java using the Servlet API a connector is need to route the requests from the Web Server to the Servlet Engine. In the case a Web Server specific connector is needed. Most of the Web Servers allow to load dynamic extentions (DLL). Some of these extentions are available in the binary builds of connectors.

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