Hi all, I have compiled and installed Squid 3.1.7 on a Linux 2.6.26 (Debian 5.0.5), and successfully tested it as a non-transparent proxy (i.e. the proxy address:port is explicitly specified in the web browser).
Now I need to use it to do transparent proxying. For this, I'm following the example at http://wiki.squid-cache.org/ConfigExamples/Intercept/CiscoAsaWccp2 . The clients will be on subnet 10.11.1.0/24. $ROUTER_IP and $SQUID_IP are both on the subnet 10.8.0.0/16. Squid has been compiled as follows: configure options: '--enable-linux-netfilter' '--enable-wccp' '--prefix=/usr' '--localstatedir=/var' '--libexecdir=/lib/squid' '--srcdir=.' '--datadir=/share/squid' '--sysconfdir=/etc/squid' 'CPPFLAGS=-I../libltdl' --with-squid=/root/squid-3.1.7 --enable-ltdl-convenience ======= Squid configuration: ======= File /etc/rc.local : modprobe ip_gre ip tunnel add wccp0 mode gre remote $ROUTER_IP local $SQUID_IP dev eth0 ifconfig wccp0 $SQUID_IP netmask 255.255.255.255 up echo 0 >/proc/sys/net/ipv4/conf/wccp0/rp_filter echo 0 >/proc/sys/net/ipv4/conf/eth0/rp_filter echo 1 >/proc/sys/net/ipv4/ip_forward iptables -t nat -A PREROUTING -i wccp0 -p tcp --dport 80 -j REDIRECT --to-port 3128 iptables -t nat -A POSTROUTING -j MASQUERADE File /etc/squid/squid.conf : I am basically using the default config, adding only the commands for transparent proxying: acl manager proto cache_object acl localhost src 127.0.0.1/32 ::1 acl to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1 acl localnet src 10.0.0.0/8 acl localnet src fc00::/7 acl localnet src fe80::/10 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 # Transparent proxying http_port 3128 transparent wccp2_router $ROUTER_IP wccp2_forwarding_method gre wccp2_return_method gre wccp2_service standard 0 # Only allow cachemgr access from localhost http_access allow manager localhost http_access deny manager # Deny requests to certain unsafe ports http_access deny !Safe_ports # Deny CONNECT to other than secure SSL ports http_access deny CONNECT !SSL_ports # We strongly recommend the following be uncommented to protect innocent # web applications running on the proxy server who think the only # one who can access services on "localhost" is a local user http_access deny to_localhost # Example rule allowing access from your local networks. # Adapt localnet in the ACL section to list your (internal) IP networks # from where browsing should be allowed http_access allow localnet http_access allow localhost # And finally deny all other access to this proxy http_access deny all # We recommend you to use at least the following line. hierarchy_stoplist cgi-bin ? # Uncomment and adjust the following to add a disk cache directory. cache_dir ufs /var/cache 50000 16 256 # Leave coredumps in the first cache dir coredump_dir /var/cache # Add any of your own refresh_pattern entries above these. 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 ======= ======= ======= Configuration of the router, a Cisco ASA 5520 firewall: ======= access-list wccp_redirect extended deny ip host $SQUID_IP any access-list wccp_redirect extended permit tcp 10.11.1.0 255.255.255.0 any eq www wccp web-cache redirect-list wccp_redirect wccp interface inside web-cache redirect in ======= ======= This does not work. The browser gives an error "Unable to connect to remote server" after a timeout. Here is is the output of "tcpdump -vvnn -i eth0 port 2048" on the Squid machine: 15:05:01.279896 IP (tos 0x0, ttl 64, id 22913, offset 0, flags [none], proto UDP (17), length 172) $SQUID_IP.2048 > $ROUTER_IP.2048: UDP, length 144 15:05:01.280090 IP (tos 0x0, ttl 255, id 5011, offset 0, flags [none], proto UDP (17), length 168) $ROUTER_IP.2048 > $SQUID_IP.2048: UDP, length 140 15:05:11.279893 IP (tos 0x0, ttl 64, id 22914, offset 0, flags [none], proto UDP (17), length 172) $SQUID_IP.2048 > $ROUTER_IP.2048: UDP, length 144 15:05:11.280083 IP (tos 0x0, ttl 255, id 20123, offset 0, flags [none], proto UDP (17), length 168) $ROUTER_IP.2048 > $SQUID_IP.2048: UDP, length 140 This is what I see on the Cisco ASA when I turn debugging on with "debug ip wccp packets": WCCP-PKT:S00: Received valid Here_I_Am packet from $SQUID_IP w/rcv_id 000001ED WCCP-PKT:S00: Sending I_See_You packet to $SQUID_IP w/ rcv_id 000001EE WCCP-PKT:S00: Received valid Here_I_Am packet from $SQUID_IP w/rcv_id 000001EE WCCP-PKT:S00: Sending I_See_You packet to $SQUID_IP w/ rcv_id 000001EF Any help is appreciated. Thanks in advance, L.
