In business networks there is a big usage of transparent proxy also home networks can use it also.
Thanks to that kind of server we can monitoring a lot of meta data and value information from client network and also prevent a lot of virus infections.
Lets assume that our server (192.168.0.10) have Ubuntu or Debian operation system installed on it and the lan network is 192.168.0.0/24.
#install squid apt-get install squid3 #lets make our own squid config file mv /etc/squid3/squid.conf /etc/squid3/squid.conf.bak vim /etc/squid3/squid.conf ###begging squid.conf ### debug_options ALL,1 acl localnet src 192.168.0.0/24 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 CONNECT method CONNECT http_access deny !Safe_ports http_access deny CONNECT !SSL_ports http_access allow localhost manager http_access deny manager http_access allow localnet http_access allow localhost http_access deny all http_port 192.168.0.10:8888 http_port 192.168.0.10:3128 intercept coredump_dir /var/spool/squid3 refresh_pattern ^ftp: 1440 20% 10080 refresh_pattern ^gopher: 1440 0% 1440 refresh_pattern -i (/cgi-bin/|?) 0 0% 0 refresh_pattern (Release|Packages(.gz)*)$ 0 20% 2880 refresh_pattern . 0 20% 4320 cache_dir /data/cache 100 16 256 cache_log /var/log/squid3/cache.log cache_mem 16 MB cache_mgr webmaster cache_replacement_policy lru cache_store_log /var/log/squid3/store.log cache_swap_high 95 cache_swap_low 90 client_lifetime 1 days connect_timeout 2 minutes error_directory /usr/share/squid3/errors/en ftp_passive on maximum_object_size 4096 KB memory_replacement_policy lru ### end squid.conf ### service squid
On server there is also software firewall (iptables) which we will use to forward connection using commands below:
iptables -t nat -A PREROUTING -s 192.168.0.10 -p tcp --dport 80 -j ACCEPT iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 3128 iptables -t nat -A POSTROUTING -j MASQUERADE iptables -t mangle -A PREROUTING -p tcp --dport 3128 -j DROP
Next, on Mikrotik router we will add firewall rules to forward chosen clients (via list SQUID_CLIENTS) to server with squid proxy:
/ip firewall mangle add chain=prerouting comment=squid dst-port=80 protocol=tcp src-address=192.168.0.10 add action=mark-routing chain=prerouting dst-port=80 in-interface=ether3 new-routing-mark=2 protocol=tcp src-address-list=SQUID_CLIENTS add chain=prerouting routing-mark=2 /ip firewall nat add action=masquerade chain=srcnat out-interface=ether1 src-address=192.168.0.0/24 /ip route add distance=1 gateway=192.168.0.10 routing-mark=2
This way we finished configuration of proxy server which will capture web traffic and don’t need to be configure on client side.
5 thoughts on “Mikrotik and Squid = Transparent Proxy”
Please give more description of your network. like interfaces details
squid is 192.168.0.10
netmask is 255.255.255.0 or /24
gateway is 192.168.0.1
any other client get ip from dhcp from network 192.168.0.0/24
To be honest not much there is to know more, most important is the squid ip to forward traffic to it.
Only thing important is to add client IP that you want to push thru squid to mikrotik SQUID_CLIENTS address list;
Thank you so much, I can track HTTP traffic now but the problem is that this doesn’t help in logging https traffic. Please post a solution for it.
you would need to install certificate on your machine and setup https-proxy that would talk with page you want to sniff. Also https was made so sniffing is very hard without access to machine you want to sniff. But if you came up with some solution.
I have generated self-certificate and tried to configure proxy but was not able to do so. If you can provide some guide or link then I really appreciate.