Apt-cacher version 1.7.22: Daemon mode
Usage:

Edit /etc/apt/apt.conf or add a configuration fragment under /etc/apt/apt.conf.d/ containing the following:

Acquire::http::Proxy "http://1984-apt-cacher:3142";
Alternatively, edit /etc/apt/sources.list so all your HTTP sources are prepended with the address of your apt-cacher machine and the port, like this:
deb http://example.debian.org/debian unstable main contrib non-free
becomes
deb http://1984-apt-cacher:3142/example.debian.org/debian unstable main contrib non-free

Configuration: /etc/apt-cacher/apt-cacher.conf

Directive Value
admin_email root@localhost
allowed_hosts *
allowed_ssl_locations
allowed_ssl_ports 443
cache_dir /var/cache/apt-cacher
clean_cache 1
concurrent_import_limit 6
curl_idle_timeout 120
curl_throttle 10
daemon_port 3142
data_timeout 120
debug 0
denied_hosts
distinct_namespaces 0
expire_hours 0
generate_reports 1
group www-data
http_proxy
libcurl_socket /var/run/apt-cacher/libcurl.socket
limit 0
limit_global 0
log_dir /var/log/apt-cacher
path_map debian ftp.is.debian.org/debian ; security security.debian.org ; dotdeb packages.dotdeb.org ; debian-security security.debian.org/debian-security
request_empty_lines 5
request_timeout 30
return_buffer_size 1048576
reverse_path_map 1
supported_archs i386, amd64
ubuntu_release_names dapper, edgy, feisty, gutsy, hardy, intrepid, jaunty, karmic, lucid, maverick, natty, oneiric, precise, quantal, raring, saucy, trusty, utopic, vivid, wily, xenial, yakkety, zesty, artful, bionic, cosmic, disco, eoan, focal, groovy, hirsute
user www-data
checksum_files_regexp (?:^|/)(?:(?:Sources|Packages)(?:\.(?:x|g)z|\.bz2)?|(?:In)?Release|Index(?:\.bz2)?)$
index_files_regexp (?:^|/)(?:Index(?:\.bz2)?|(?:Sources|Packages|release)(?:\.(?:x|g)z|\.bz2)?|Release(?:\.gpg)?|InRelease|Contents-(?:[a-z]+-)?[a-zA-Z0-9]+\.gz|(?:srclist|pkglist)\.[a-z-]+\.bz2|Components-(?:i386|amd64|all)\.yml\.(?:x|g)z|icons-(64|128)x\g{-1}\.tar\.(?:x|g)z|Translation-[a-z]{2,3}(?:_[A-Z]{2}(?:\.[a-zA-Z0-9-]+)?)?(?:\.gz|\.bz2|\.xz|\.lzma)?)$
installer_files_regexp (?:^|/)(?:vmlinuz|linux|initrd\.gz|(?:[a-z0-9][-+.a-z0-9]*_(?:\d+:)?[0-9][-+:.~a-zA-Z0-9]*[_\.])?changelog|NEWS\.Debian|(?:dapper|edgy|feisty|gutsy|hardy|intrepid|jaunty|karmic|lucid|maverick|natty|oneiric|precise|quantal|raring|saucy|trusty|utopic|vivid|wily|xenial|yakkety|zesty|artful|bionic|cosmic|disco|eoan|focal|groovy|hirsute)\.tar\.gz(?:\.gpg)?|(?:by-hash/(?i:MD5SUM/[0-9a-f]{32}|SHA1/[0-9a-f]{40}|SHA256/[0-9a-f]{64}))|(?:Devel|EOL)?ReleaseAnnouncement(?:\.html)?|meta-release(?:-lts)?(?:-(?:development|proposed))?)$
package_files_regexp (?:(?:^|/)[a-z0-9][-+.a-z0-9]*_(?:\d+:)?[0-9][-+:.~a-zA-Z0-9]*(?:_(?:i386|amd64|all)\.(?:u|d)?deb|\.dsc|\.tar\.(?:gz|bz2|xz|lzma)(?:\.asc)?|\.diff\.gz)|\.rpm|index\.db-.+\.gz|\.jigdo|\.template)$
pdiff_files_regexp (?:^|/)(?:T-2\d{3}-\d{2}-\d{2}-\d{4}\.\d{2}-F-)?2\d{3}-\d{2}-\d{2}-\d{4}\.\d{2}\.gz$
skip_checksum_files_regexp (?:^|/)(?:(?:In)?Release|Release\.gpg)$
soap_url_regexp ^(?:http://)?bugs\.debian\.org(?::80)?/cgi-bin/soap\.cgi$

License

Apt-cacher is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

Apt-cacher is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

A copy of the GNU General Public License is available as /usr/share/common-licenses/GPL in the Debian GNU/Linux distribution or on the World Wide Web at http://www.gnu.org/copyleft/gpl.html. You can also obtain it by writing to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.