apt-transport-http - Man Page

The environment variable http_proxy is supported for system wide configuration​. Proxies specific to APT can be configured via the option Acquire::http::Proxy​. Proxies which should be used only for certain hosts can be specified via Acquire::http::Proxy::host​. Even more fine-grained control can be achieved via proxy autodetection, detailed further below​. All these options use the URI format scheme://[[user][:pass]@]host[:port]/​. Supported URI schemes are socks5h (SOCKS5 with remote DNS resolution), http and https​. Authentication details can be supplied via apt_auth.conf(5) instead of including it in the URI directly​.

The various APT configuration options support the special value DIRECT meaning that no proxy should be used​. The environment variable no_proxy is also supported for the same purpose​.

Furthermore, there are three settings provided for cache control with HTTP/1​.1 compliant proxy caches: Acquire::http::No-Cache tells the proxy not to use its cached response under any circumstances​. Acquire::http::Max-Age sets the allowed maximum age (in seconds) of an index file in the cache of the proxy​. Acquire::http::No-Store specifies that the proxy should not store the requested archive files in its cache, which can be used to prevent the proxy from polluting its cache with (big) ​.deb files​.

Acquire::http::Proxy-Auto-Detect can be used to specify an external command to discover the HTTP proxy to use​. The first and only parameter is a URI denoting the host to be contacted, to allow for host-specific configuration​. APT expects the command to output the proxy on stdout as a single line in the previously specified URI format or the word DIRECT if no proxy should be used​. No output indicates that the generic proxy settings should be used​.

Note that auto-detection will not be used for a host if a host-specific proxy configuration is already set via Acquire::http::Proxy::host​.

See the squid-deb-proxy-client(1) and auto-apt-proxy(1) packages for example implementations​.

This option takes precedence over the legacy option name Acquire::http::ProxyAutoDetect​.

The option Acquire::http::Timeout sets the timeout timer used by the method; this value applies to the connection as well as the data timeout​.

The used bandwidth can be limited with Acquire::http::Dl-Limit which accepts integer values in kilobytes per second​. The default value is 0 which deactivates the limit and tries to use all available bandwidth​. Note that this option implicitly disables downloading from multiple servers at the same time​.

The setting Acquire::http::Pipeline-Depth can be used to enable HTTP pipelining (RFC 2616 section 8​.1​.2​.2) which can be beneficial e​.g​. on high-latency connections​. It specifies how many requests are sent in a pipeline​. APT tries to detect and work around misbehaving webservers and proxies at runtime, but if you know that yours does not conform to the HTTP/1​.1 specification, pipelining can be disabled by setting the value to 0​. It is enabled by default with the value 10​.

Acquire::http::AllowRedirect controls whether APT will follow redirects, which is enabled by default​.

Acquire::http::User-Agent can be used to set a different User-Agent for the http download method as some proxies allow access for clients only if the client uses a known identifier​.

Acquire::http::SendAccept is enabled by default and sends an Accept: text/* header field to the server for requests without file extensions to prevent the server from attempting content negotiation​.