1APT-TRANSPORT-HTTP(1)                 APT                APT-TRANSPORT-HTTP(1)
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3
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NAME

6       apt-transport-http - APT transport for downloading via the Hypertext
7       Transfer Protocol (HTTP)
8

DESCRIPTION

10       This APT transport allows the use of repositories accessed via the
11       Hypertext Transfer Protocol (HTTP). It is available by default and
12       probably the most used of all transports. Note that a transport is
13       never called directly by a user but used by APT tools based on user
14       configuration.
15
16       HTTP is an unencrypted transport protocol meaning that the whole
17       communication with the remote server (or proxy) can be observed by a
18       sufficiently capable attacker commonly referred to as a "man in the
19       middle" (MITM). However, such an attacker can not modify the
20       communication to compromise the security of your system, as APT's data
21       security model is independent of the chosen transport method. This is
22       explained in detail in apt-secure(8). An overview of available
23       transport methods is given in sources.list(5).
24

OPTIONS

26       Various options can be set in an apt.conf(5) file to modify its
27       behavior, ranging from proxy configuration to workarounds for specific
28       server limitations.
29
30   Proxy Configuration
31       The environment variable http_proxy is supported for system wide
32       configuration. Proxies specific to APT can be configured via the option
33       Acquire::http::Proxy. Proxies which should be used only for certain
34       hosts can be specified via Acquire::http::Proxy::host. Even more
35       fine-grained control can be achieved via proxy autodetection, detailed
36       further below. All these options use the URI format
37       scheme://[[user][:pass]@]host[:port]/. Supported URI schemes are
38       socks5h (SOCKS5 with remote DNS resolution), http and https.
39       Authentication details can be supplied via apt_auth.conf(5) instead of
40       including it in the URI directly.
41
42       The various APT configuration options support the special value DIRECT
43       meaning that no proxy should be used. The environment variable no_proxy
44       is also supported for the same purpose.
45
46       Furthermore, there are three settings provided for cache control with
47       HTTP/1.1 compliant proxy caches: Acquire::http::No-Cache tells the
48       proxy not to use its cached response under any circumstances.
49       Acquire::http::Max-Age sets the allowed maximum age (in seconds) of an
50       index file in the cache of the proxy.  Acquire::http::No-Store
51       specifies that the proxy should not store the requested archive files
52       in its cache, which can be used to prevent the proxy from polluting its
53       cache with (big) .deb files.
54
55   Automatic Proxy Configuration
56       Acquire::http::Proxy-Auto-Detect can be used to specify an external
57       command to discover the HTTP proxy to use. The first and only parameter
58       is a URI denoting the host to be contacted, to allow for host-specific
59       configuration. APT expects the command to output the proxy on stdout as
60       a single line in the previously specified URI format or the word DIRECT
61       if no proxy should be used. No output indicates that the generic proxy
62       settings should be used.
63
64       Note that auto-detection will not be used for a host if a host-specific
65       proxy configuration is already set via Acquire::http::Proxy::host.
66
67       See the squid-deb-proxy-client(1) and auto-apt-proxy(1) packages for
68       example implementations.
69
70       This option takes precedence over the legacy option name
71       Acquire::http::ProxyAutoDetect.
72
73   Connection Configuration
74       The option Acquire::http::Timeout sets the timeout timer used by the
75       method; this value applies to the connection as well as the data
76       timeout.
77
78       The used bandwidth can be limited with Acquire::http::Dl-Limit which
79       accepts integer values in kilobytes per second. The default value is 0
80       which deactivates the limit and tries to use all available bandwidth.
81       Note that this option implicitly disables downloading from multiple
82       servers at the same time.
83
84       The setting Acquire::http::Pipeline-Depth can be used to enable HTTP
85       pipelining (RFC 2616 section 8.1.2.2) which can be beneficial e.g. on
86       high-latency connections. It specifies how many requests are sent in a
87       pipeline. APT tries to detect and work around misbehaving webservers
88       and proxies at runtime, but if you know that yours does not conform to
89       the HTTP/1.1 specification, pipelining can be disabled by setting the
90       value to 0. It is enabled by default with the value 10.
91
92       Acquire::http::AllowRedirect controls whether APT will follow
93       redirects, which is enabled by default.
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95       Acquire::http::User-Agent can be used to set a different User-Agent for
96       the http download method as some proxies allow access for clients only
97       if the client uses a known identifier.
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99       Acquire::http::SendAccept is enabled by default and sends an Accept:
100       text/* header field to the server for requests without file extensions
101       to prevent the server from attempting content negotiation.
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EXAMPLES

104           Acquire::http {
105                Proxy::example.org "DIRECT";
106                Proxy "socks5h://apt:pass@127.0.0.1:9050";
107                Proxy-Auto-Detect "/usr/local/bin/apt-http-proxy-auto-detect";
108                No-Cache "true";
109                Max-Age "3600";
110                No-Store "true";
111                Timeout "10";
112                Dl-Limit "42";
113                Pipeline-Depth "0";
114                AllowRedirect "false";
115                User-Agent "My APT-HTTP";
116                SendAccept "false";
117           };
118

SEE ALSO

120       apt.conf(5) apt_auth.conf(5) sources.list(5)
121

BUGS

123       APT bug page[1]. If you wish to report a bug in APT, please see
124       /usr/share/doc/debian/bug-reporting.txt or the reportbug(1) command.
125

AUTHOR

127       APT team
128

NOTES

130        1. APT bug page
131           http://bugs.debian.org/src:apt
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135APT 2.3.11                       04 April 2019           APT-TRANSPORT-HTTP(1)
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