There are many reasons to start hosting an outgoing proxy. Mine was slow upstream servers. But if, for whatever reason, you wish to use an outgoing proxy, this blogpost might be helpful.
The steps are as follows:
- Install the software (squid on Debian Linux in my case)
- Configure the software (squid on Debian Linux)
- Configure your various software to accept the proxy intercepting the TLS secure connections
- Redirect all traffic through the proxy, with some exceptions if needed. (Websockets are not supported, so you will need to put some exception in for that)
Install
- Debian doesn't include tls interception (called ssl-bump in squid) support in the default package. If you want this, you need to install squid-openssl.
apt install squid-openssl
Configure
- Prepare the Certificate Authority (CA)
mkdir -p /etc/squid/cert/ cd /etc/squid/cert/ # This puts the private key and the self-signed certificate in the same file openssl req -new -newkey rsa:4096 -sha256 -days 3650 -nodes -x509 -keyout myCA.pem -out myCA.pem - Create a config file /etc/squid/squid.conf
workers 4 acl localnet dst 0.0.0.1-0.255.255.255 # RFC 1122 "this" network (LAN) acl localnet dst 10.0.0.0/8 # RFC 1918 local private network (LAN) acl localnet dst 100.64.0.0/10 # RFC 6598 shared address space (CGN) acl localnet dst 169.254.0.0/16 # RFC 3927 link-local (directly plugged) machines acl localnet dst 172.16.0.0/12 # RFC 1918 local private network (LAN) acl localnet dst 192.168.0.0/16 # RFC 1918 local private network (LAN) acl localnet dst fc00::/7 # RFC 4193 local private network range acl localnet dst fe80::/10 # RFC 4291 link-local (directly plugged) machines acl localnet dst 2a02:a44e:5504::/56 acl tunnelips dst "/etc/squid/tunnelips.list" acl SSL_ports port 443 acl SSL_ports port 8443 acl SSL_ports port 8843 acl SSL_ports port 5281 acl SSL_ports port 9091 acl Safe_ports port 80 # http acl Safe_ports port 21 # ftp acl Safe_ports port 443 # https acl Safe_ports port 8443 # https acl Safe_ports port 8843 # https acl Safe_ports port 70 # gopher acl Safe_ports port 210 # wais acl Safe_ports port 1025-65535 # unregistered ports acl Safe_ports port 280 # http-mgmt acl Safe_ports port 488 # gss-http acl Safe_ports port 591 # filemaker acl Safe_ports port 777 # multiling http acl Safe_ports port 9091 # transmission acl CONNECT method CONNECT acl step1 at_step SslBump1 acl step2 at_step SslBump2 acl step3 at_step SslBump3 acl tunnelsites ssl::server_name_regex -i "/etc/squid/tunnelsites.list" http_access deny !Safe_ports http_access deny CONNECT !SSL_ports http_access allow localhost manager http_access deny manager include /etc/squid/conf.d/* http_access allow localnet http_access allow localhost http_access allow all http_access deny all on_unsupported_protocol tunnel all http_port 3128 ssl-bump tls-cert=/etc/squid/cert/SQUID_CA.pem generate-host-certificates=on dynamic_cert_mem_cache_size=8MB http_port 3129 intercept https_port 3131 intercept ssl-bump tls-cert=/etc/squid/cert/SQUID_CA.pem generate-host-certificates=on dynamic_cert_mem_cache_size=8MB https_port 443 intercept ssl-bump tls-cert=/etc/squid/cert/SQUID_CA.pem generate-host-certificates=on dynamic_cert_mem_cache_size=8MB tls_outgoing_options min-version=1.2 cafile=/etc/ssl/certs/ca-certificates.crt ssl_bump splice tunnelsites ssl_bump splice step1 localnet ssl_bump splice step1 tunnelips ssl_bump peek step1 ssl_bump splice tunnelsites ssl_bump bump sslcrtd_program /usr/lib/squid/security_file_certgen -s /var/spool/squid/ssl_db -M 40MB sslcrtd_children 16 startup=5 idle=3 sslproxy_cert_error deny all server_idle_pconn_timeout 10 minutes cache_mem 256 MB memory_cache_mode always maximum_object_size_in_memory 5 MB logformat bumpsquid %ts.%03tu %6tr %>a %Ss/%03>Hs %ssl::bump_mode %<st %rm %ru %[un %Sh/%<a %mt access_log daemon:/var/log/squid/access.log bumpsquid coredump_dir /var/spool/squid refresh_pattern -i (/cgi-bin/|\?) 0 0% 0 refresh_pattern -i .(gif|png|jpg|jpeg|ico)$ 10080 90% 43200 override-expire ignore-no-cache ignore-no-store ignore-private ignore-auth refresh_pattern -i gstatic\.com 10080 90% 43200 override-expire ignore-no-cache ignore-no-store ignore-private ignore-auth refresh_pattern -i .(iso|avi|wav|mp3|mp4|mpeg|swf|flv|x-flv)$ 43200 90% 432000 override-expire ignore-no-cache ignore-no-store ignore-private ignore-auth refresh_pattern -i .(deb|rpm|exe|zip|tar|tgz|ram|rar|bin|ppt|doc|tiff|InRelease|Packages.gz)$ 10080 90% 43200 override-expire ignore-no-cache ignore-no-store ignore-private ignore-auth refresh_pattern -i .(css|js)$ 10080 90% 43200 override-expire ignore-no-cache ignore-no-store ignore-private ignore-auth refresh_pattern -i .index.(html|htm)$ 0 40% 10080 override-expire ignore-no-cache ignore-no-store ignore-private ignore-auth refresh_pattern -i .(html|htm)$ 1440 40% 40320 override-expire ignore-no-cache ignore-no-store ignore-private ignore-auth refresh_pattern . 0 40% 40320 shutdown_lifetime 1 seconds global_internal_static off dns_v4_first on forwarded_for delete pipeline_prefetch on max_filedesc 204800 fqdncache_size 2048 ipcache_size 2048 ipcache_low 95 ipcache_high 98 cache_swap_low 95 cache_swap_low 98 quick_abort_min 0 quick_abort_max 0 quick_abort_pct 95 range_offset_limit -1 request_header_max_size 200 KB reply_header_max_size 200 KB memory_pools off buffered_logs off log_icp_queries off logfile_rotate 1 icp_hit_stale on query_icmp off reload_into_ims on negative_ttl 2 minutes vary_ignore_expire on half_closed_clients off high_page_fault_warning 2 nonhierarchical_direct on prefer_direct off cachemgr_passwd none all client_db on forwarded_for on via on max_stale 1 month - Create the certificate database by issuing
/usr/lib/squid/security_file_certgen -c -s /var/spool/squid/ssl_db -M 4MBand correct access rights with
chmod -R proxy:proxy /var/spool/squid/ssl_db - Restart squid with
systemctl restart squid
Configure client software
- Prepare the CA certificate for use by browsers.
# This can be added to browsers openssl x509 -in /etc/squid/cert/myCA.pem -outform DER -out /tmp/myCA.der - Add the squid CA to the system wide ca-certificates
# Copy the CA to the ca-certificates directory sudo openssl x509 -in /etc/squid/cert/myCA.pem -out /usr/share/ca-certificates/myCA.crt - Add the line
myCA.crtto /etc/ca-certificates.conf and runsudo update-ca-certificates - For firefox (this is what I use), open the settings, find security devices and add
/usr/lib/x86_64-linux-gnu/pkcs11/p11-kit-trust.soas a security device. This means Firefox will also trust the system wide CAs. - For other browsers, you can import the /tmp/myCA.der as a Certificate Authority.
Force all traffic through the proxy
- Install packages for firewall management if not already installed:
sudo apt install netfilter-persistent iptables-persistent - Configure the firewall rules
sudo iptables -t nat -A OUTPUT -p tcp -m tcp --dport 80 -m owner --uid-owner root -j RETURN sudo iptables -t nat -A OUTPUT -p tcp -m tcp --dport 80 -m owner --uid-owner proxy -j RETURN sudo iptables -t nat -A OUTPUT -p tcp -m tcp --dport 443 -m owner --uid-owner root -j RETURN sudo iptables -t nat -A OUTPUT -p tcp -m tcp --dport 443 -m owner --uid-owner proxy -j RETURN sudo iptables -t nat -A OUTPUT -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3129 sudo iptables -t nat -A OUTPUT -p tcp -m tcp --dport 443 -j REDIRECT --to-ports 3131 - Save the rules:
sudo netfilter-persistent save
Have a cup of tea
Because you're done. You might need to relogin/reboot for the p11-kit stuff to take effect.