Greetings, I installed a squid 3.1.10.i686 squid to a centos 6.2i686. The proxy is working fine with the default config. After I decided to use it as a transparent proxy, I added two lines to config: http_proxy 10.0.5.1:3128 transparent, always_direct allow all http_port 10.0.5.1:3128 transparent # # Recommended minimum configuration: # acl manager proto cache_object #acl localhost src 127.0.0.1/32 ::1 acl localhost src 127.0.0.1/32 #acl to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1 acl to_localhost dst 127.0.0.0/8 0.0.0.0/32 # Example rule allowing access from your local networks. # Adapt to list your (internal) IP networks from where browsing # should be allowed acl localnet src 10.0.0.0/8 # RFC1918 possible internal network #acl localnet src 172.16.0.0/12 # RFC1918 possible internal network #acl localnet src 192.168.0.0/16 # RFC1918 possible internal network #acl localnet src fc00::/7 # RFC 4193 local private network range #acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines 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 # # Recommended minimum Access Permission configuration: # # 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 # # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS # # 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 # Squid normally listens to port 3128 http_port 3128 # 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/spool/squid 100 16 256 # Leave coredumps in the first cache dir coredump_dir /var/spool/squid # 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 always_direct allow all There are 2 iptables rule too: -A PREROUTING -i lo -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3128 -A PREROUTING -i eth0 -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3128 eth0 is the local NIC, eth1 is for internet. ipv4_forward is enabled. [root at atom squid]# iptables -S -t nat -P PREROUTING ACCEPT -P POSTROUTING ACCEPT -P OUTPUT ACCEPT -A PREROUTING -i lo -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3128 -A PREROUTING -i eth0 -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3128 -A POSTROUTING -o eth1 -j MASQUERADE [root at atom squid]# iptables -S -P INPUT DROP -P FORWARD ACCEPT -P OUTPUT ACCEPT -A INPUT -i eth1 -m state --state RELATED,ESTABLISHED -j ACCEPT -A INPUT -p udp -m udp --dport 53 -j ACCEPT -A INPUT -p tcp -m tcp --dport 53 -j ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -i tun+ -j ACCEPT -A INPUT -i eth0 -j ACCEPT -A INPUT -p icmp -j ACCEPT -A INPUT -j DROP -A FORWARD -j ACCEPT -A OUTPUT -j ACCEPT The cache.log tells me about strange errors: 2012/01/22 00:23:51| Starting Squid Cache version 3.1.4 for i386-koji-linux-gnu... 2012/01/22 00:23:51| Process ID 4981 2012/01/22 00:23:51| With 1024 file descriptors available 2012/01/22 00:23:51| Initializing IP Cache... 2012/01/22 00:23:51| DNS Socket created at [::], FD 7 2012/01/22 00:23:51| Adding nameserver 192.168.4.254 from /etc/resolv.conf 2012/01/22 00:23:51| Adding nameserver 192.168.5.254 from /etc/resolv.conf 2012/01/22 00:23:51| User-Agent logging is disabled. 2012/01/22 00:23:51| Referer logging is disabled. 2012/01/22 00:23:51| Unlinkd pipe opened on FD 12 2012/01/22 00:23:51| Local cache digest enabled; rebuild/rewrite every 3600/3600 sec 2012/01/22 00:23:51| Store logging disabled 2012/01/22 00:23:51| Swap maxSize 0 + 262144 KB, estimated 20164 objects 2012/01/22 00:23:51| Target number of buckets: 1008 2012/01/22 00:23:51| Using 8192 Store buckets 2012/01/22 00:23:51| Max Mem size: 262144 KB 2012/01/22 00:23:51| Max Swap size: 0 KB 2012/01/22 00:23:51| Using Least Load store dir selection 2012/01/22 00:23:51| Set Current Directory to /var/spool/squid 2012/01/22 00:23:51| Loaded Icons. 2012/01/22 00:23:51| Accepting HTTP connections at [::]:3128, FD 13. 2012/01/22 00:23:51| HTCP Disabled. 2012/01/22 00:23:51| Squid modules loaded: 0 2012/01/22 00:23:51| Adaptation support is off. 2012/01/22 00:23:51| Ready to serve requests. 2012/01/22 00:23:52| storeLateRelease: released 0 objects 2012/01/22 00:23:56| idnsGrokReply: Malformed DNS response 2012/01/22 00:24:01| idnsGrokReply: Malformed DNS response 2012/01/22 00:24:02| idnsGrokReply: Malformed DNS response 2012/01/22 00:24:06| idnsGrokReply: Malformed DNS response 2012/01/22 00:24:08| idnsGrokReply: Malformed DNS response 2012/01/22 00:24:13| idnsGrokReply: Malformed DNS response 2012/01/22 00:24:16| idnsGrokReply: Malformed DNS response 2012/01/22 00:24:23| idnsGrokReply: Malformed DNS response I tried to get another verision of squid, but 3.1.4, and 3.1.10 makes the same error. On a fedora 16 x86_64, with the same config as above, there is no error, and works perfectly, with the same iptables rule. Any idea, how can I fix it, or what I may configured wrong? Thanks Balazs