[squid-users] squid tproxy

Vieri rentorbuy at yahoo.com
Fri Aug 28 17:27:13 UTC 2015


[reposting a trimmed-down message]

My goal is to allow lan users to access a greater number of sites if they explicitly configure the squid proxy server in their browsers and authenticate. If they don't then traffic to port 80 and 443 will be transparently redirected to a squid proxy server by the corporate firewall (in my case, firewall and squid are on the same machine).

Since I noticed that I cannot REQUIRE proxy_auth and create an additional http_port for tproxy without authentication, I merely created two instances of squid.

The first instance requires authentication and listens on port 3128. All works fine when setting up the proxy address and port 3128 (or via wpad.dat) on the client.

The second instance does not require authentication and listens on port 3129 in tproxy mode and on port 3130 in forward proxy mode.

The firewall on the same machine as squid (iptables) redirects port 80 to 3129

I tried connecting from a Firefox client browser (lan IP addr. without proxy manually configured to internet host

The second squid proxy instance handles the connection but fails with a connection timeout (see log below).

squid.tproxy.conf (of second instance):

acl SSL_ports port 443
acl Safe_ports port 80 # http
acl Safe_ports port 21 # ftp
acl Safe_ports port 443 # 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 901 # SWAT
http_access deny !Safe_ports
http_access deny CONNECT !SSL_ports
http_access allow localhost manager
http_access deny manager
include /etc/squid/squid.custom.rules.tproxy
http_access allow localhost
http_access deny all
coredump_dir /var/cache/squid
refresh_pattern ^ftp: 1440 20% 10080
refresh_pattern ^gopher: 1440 0% 1440
refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
refresh_pattern . 0 20% 4320
pid_filename /run/squid.tproxy.pid
cache_dir ufs /var/cache/squid.tproxy 100 16 256


access_log daemon:/var/log/squid/access.tproxy.log squid
cache_log /var/log/squid/cache.tproxy.log
http_access allow all
email_err_data on
error_directory /usr/share/squid/errors/HMAN
debug_options rotate=1 ALL,5
append_domain .mydomain.org
http_port 3130
http_port 3129 tproxy
dns_v4_first on

squid 3.5.6
kernel 4.1.4


lsmod shows xt_TPROXY, nf_conntrack, xt_socket

Here's the log (connecting from client browser at to internet host at


What is causing the timeout?

Is there something wrong with my squid configuration or should I look elsewhere?



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