[CentOS] squid transparent proxy problem

João Rodrigues joao.rodrigues at gmail.com
Mon Jan 23 00:00:44 UTC 2012


Please verify you resolv.conf

João Rodrigues

On Sat, Jan 21, 2012 at 10:33 PM, Hüvely Balázs <balazs.huvely at gmail.com>wrote:

> 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
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