February 2010 - tproxy - lists.balabit.hu

EADDRNOTAVAIL from connect, but only sometimes
by Ron Parker 15 Apr '10

15 Apr '10

Hi, We are using the tproxy patch for Linux 2.6.24 (Ubuntu 8.0.4). When placing outgoing connections, we use the original socket address (4-tuple) in the bind and set SO_REUSEADDR on the socket. The sequence we are having difficulty with is: * Client connects to transparent proxy * Transparent proxy connects to remote server * Normal data transfer... * Remote server closes the connection (but client connection is maintained) * Transparent proxy attempts to connect again to remote server using the original 4-tuple (again) o Bind succeeds o Connect fails with EADDRNOTAVAIL The original socket is probably in TIME_WAIT at this point. I thought the SO_REUSEADDR would take care of the problem. What am I missing here? Thanks. Ron

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TPROXY behavior when there is no listening socket at the target port
by Ashwani Wason 15 Apr '10

15 Apr '10

Hi All, If one has a TPROXY rule that redirects the packets to a local socket on which there is no one listening then the SYN packets keep getting dropped silently. Is this expected? Without knowing that this would happen my natural expectation was that a RST would be sent by local TCP. Is this by design or a bug? Thanks, - Ashwani

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How does 'dev lo' in tproxy routing rule really work?
by Ashwani Wason 15 Apr '10

15 Apr '10

I want to understand the tproxy rules that have been kindly written for us in http://www.balabit.com/downloads/files/tproxy/README.txt. I understand every aspect of those rules, iptables and iproute2, except this one small highlighted bit in the last rule. ip route add local 0.0.0.0/0 *dev lo* table 100 # ip route show table 100 local default dev lo scope host So packets with fwmark 1 get selected for this routing table, which assumes that all destinations are assigned to this host and hence delivers the packets locally. But the output device is set to 'lo', which is the local loopback device. However even if the proxy is not listening on the IP of lo (say it only has the socket for eth0 and the packet came in on eth0), it still receives the packet. So is the 'lo' here just a way to indicate local delivery to the associated physical interface and does not really represent the actual output interface? Can someone please shed some light on this that is more than a simple yes/no answer? Thank you, - Ashwani

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Deployment TPROXY
by V. Feitoza 13 Feb '10

13 Feb '10

Good staff I have the following architecture: Arch Linux kernel: 2.6.30 iptables: 1.4.6 ebtables: 2.0.9 squid: 3.1.0.14 Network: eth1: 0.0.0.0 eth2: 0.0.0.0 br0: 172.16.2.3/12 route: 172.16.0.1 Firewall rules: cd /proc/sys/net/bridge/ for i in * do echo 0 > $i done unset i iptables -t mangle -N DIVERT iptables -t mangle -A DIVERT -j MARK --set-mark 1 iptables -t mangle -A DIVERT -j ACCEPT iptables -t mangle -A PREROUTING -p tcp -m socket -j DIVERT iptables -t mangle -A PREROUTING -p tcp --dport 80 -j TPROXY --tproxy-mark 0x1/0x1 --on-port 3129 ebtables -t broute -A BROUTING -i eth1 -p ipv4 --ip-proto tcp --ip-dport 80 -j redirect --redirect-target DROP ebtables -t broute -A BROUTING -i eth2 -p ipv4 --ip-proto tcp --ip-dport 80 -j redirect --redirect-target DROP ip rule add fwmark 1 lookup 100 ip route add local 0.0.0.0/0 dev lo table 100 Sysctl: net.ipv4.conf.default.rp_filter=0 net.ipv4.conf.default.forwarding=1 net.ipv4.conf.all.forwarding=1 net.ipv4.ip_nonlocal_bind=1 net.ipv4.ip_forward=1 Squid.conf acl all src all acl manager proto cache_object acl localhost src 127.0.0.1/32 acl to_localhost dst 127.0.0.0/8 0.0.0.0/32 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 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 allow manager localhost http_access deny manager http_access deny !Safe_ports http_access deny CONNECT !SSL_ports http_access allow localnet http_access deny all icp_access allow localnet icp_access deny all http_port 3128 http_port 3129 tproxy hierarchy_stoplist cgi-bin ? access_log /var/log/squid/access.log 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 #acl shoutcast rep_header X-HTTP09-First-Line ^ICY.[0-9] #upgrade_http0.9 deny shoutcast #acl apache rep_header Server ^Apache #broken_vary_encoding allow apache cache_mgr mail(a)mai.com visible_hostname agros.mail.com cache_effective_user proxy cache_effective_group proxy maximum_object_size 10 MB cache_dir aufs /var/cache/squid/cache 80000 16 256 coredump_dir /var/cache/squid/cache/ cache_store_log /var/log/squid/store.log cache_log /var/log/squid/cache.log access_log /var/log/squid/access.log squid pid_filename /var/run/squid.pid tcp_outgoing_address 172.16.2.3 debug_options ALL,1 89,6 Now comes the problem: Sometimes browsing but slowly and in most cases customers do not open anything. Thanks Victor Feitoza.

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Re: [tproxy] iptable_tproxy
by nicolas normand 11 Feb '10

11 Feb '10

I would suggest you use: - iptables 1.4.6: I don't remember if iptables 1.4.2 needs to be patched or not - linux 2.6.31: yes, it has built-in tproxy. You need options "Transparent proxying support (EXPERIMENTAL)", "TPROXY" target support (EXPERIMENTAL) and "socket" match support (EXPERIMENTAL) Don't use the 2.6.32, something changed about rp_filters and I couldn't make tproxy to work with it. Maybe someone else know how to do. The problem was fixed on the 2.6.33 (which is not yet released), but you'll need to set a new sysctl call: sysctl net.ipv4.conf.lo.src_valid_mark=1 For iptables/ebtables rulez, I based my configuration on this post: https://lists.balabit.hu/pipermail/tproxy/2010-January/001211.html Bye, Nicolas 2010/2/11 Alexander Dultsev <alexander.dooltsev(a)gmail.com>: > hi Nicolas, > thanks for the fast reply, and sorry about my spontaneous question - yes, > it's about using iptables 1.4.2 with a patched Debian kernel 2.6.27-wt6 > (tproxy patch) or not patched 2.6.31 (the 2.6.31 has it in-built, am I > correct?) > So, 1) is iptables 1.4.2 + kernel 2.6.31 ok to go for tproxy functionality? > 2) how would you make it working then? > Thanks, > Alex. > > > On Thu, Feb 11, 2010 at 9:14 AM, nicolas normand <doomyster(a)gmail.com> > wrote: >> >> I suppose you are speaking of the tproxy table. It was removed some >> time ago (I don't remember when), now I could make tproxy to work with >> just the mangle table, and a 2.6.31 or 2.6.33 linux kernel. >> >> Bye, >> Nicolas >> >> 2010/2/11 Alexander Dultsev <alexander.dooltsev(a)gmail.com>: >> > Hello, >> > perhaps it's covered in some place here (if so, could you please point >> > to >> > the right direction) - is entry iptables_tproxy.ko missing under tproxy >> > 4.x.x version (so things like 'iptables -F tproxy -L' cannot be called)? >> > I >> > can see, for instance, 'iptables_raw' etc, but not the above in my >> > /lib/modules/... directory. >> > Thanks, >> > Alex. >> > _______________________________________________ >> > tproxy mailing list >> > tproxy(a)lists.balabit.hu >> > https://lists.balabit.hu/mailman/listinfo/tproxy >> > >> > > >

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iptable_tproxy
by Alexander Dultsev 11 Feb '10

11 Feb '10

Hello, perhaps it's covered in some place here (if so, could you please point to the right direction) - is entry iptables_tproxy.ko missing under tproxy 4.x.x version (so things like 'iptables -F tproxy -L' cannot be called)? I can see, for instance, 'iptables_raw' etc, but not the above in my /lib/modules/... directory. Thanks, Alex.

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Need Help
by Adnan Shahzad 04 Feb '10

04 Feb '10

Dear All, I configured Tproxy with squid + NTLM + AD, everything works fine.... My problem is that "HTTPS" .... https request Time out and when I remove only secure portion in Browser setting it work fine.. Kindly help me Access.log: 1264582167.890 3 10.10.0.40 TCP_DENIED/407 7673 CONNECT www.google.com:443<http://www.google.com:443> - NONE/- text/html 1264582167.900 5 10.10.0.40 TCP_DENIED/407 7883 CONNECT www.google.com:443<http://www.google.com:443> - NONE/- text/html 1264582174.569 3 10.10.0.40 TCP_DENIED/407 7673 GET http://mail.yahoo.com/ - NONE/- text/html 1264582174.580 6 10.10.0.40 TCP_DENIED/407 7883 GET http://mail.yahoo.com/ - NONE/- text/html 1264582175.616 1026 10.10.0.40 TCP_MISS/302 700 GET http://mail.yahoo.com/ mydomain\Username DIRECT/69.147.112.160 text/html 1264582175.625 4 10.10.0.40 TCP_DENIED/407 7673 CONNECT login.yahoo.com:443 - NONE/- text/html 1264582175.636 7 10.10.0.40 TCP_DENIED/407 7883 CONNECT login.yahoo.com:443 - NONE/- text/html 1264582177.020 4 10.10.0.40 TCP_DENIED/407 7673 CONNECT login.facebook.com:443 - NONE/- text/html 1264582177.030 5 10.10.0.40 TCP_DENIED/407 7883 CONNECT login.facebook.com:443 - NONE/- text/html 1264582214.286 5 10.10.0.40 TCP_DENIED/403 378 GET http://91.212.226.182/loader.exe - NONE/- text/html 1264582223.319 46277 10.10.0.40 TCP_MISS/000 0 CONNECT login.facebook.com:443 MYDOMAIN\USERNAME NONE/- - 1264582223.338 8 10.10.0.40 TCP_DENIED/407 7673 CONNECT login.facebook.com:443 - NONE/- text/html 1264582223.366 13 10.10.0.40 TCP_DENIED/407 7883 CONNECT login.facebook.com:443 - NONE/- text/html 1264582227.958 60055 10.10.0.40 TCP_MISS/504 0 CONNECT www.google.com:443<http://www.google.com:443> MYDOMAIN\USERNAME DIRECT/216.239.61.104 - 1264582235.984 1 10.10.0.40 TCP_DENIED/407 7673 CONNECT login.facebook.com:443 - NONE/- text/html 1264582235.993 2 10.10.0.40 TCP_DENIED/407 7883 CONNECT login.facebook.com:443 - NONE/- text/html 1264582238.832 2 10.10.0.40 TCP_DENIED/407 7673 GET http://mail.yahoo.com/ - NONE/- text/html 1264582238.842 4 10.10.0.40 TCP_DENIED/407 7883 GET http://mail.yahoo.com/ - NONE/- text/html 1264582240.098 1246 10.10.0.40 TCP_MISS/302 700 GET http://mail.yahoo.com/ MYDOMAIN\USERNAME DIRECT/69.147.112.160 text/html 1264582240.104 2 10.10.0.40 TCP_DENIED/407 7673 CONNECT login.yahoo.com:443 - NONE/- text/html 1264582240.113 4 10.10.0.40 TCP_DENIED/407 7883 CONNECT login.yahoo.com:443 - NONE/- text/html 1264582304.251 1 10.10.0.40 TCP_DENIED/407 7673 GET http://mail.yahoo.com/ - NONE/- text/html 1264582304.262 4 10.10.0.40 TCP_DENIED/407 7883 GET http://mail.yahoo.com/ - NONE/- text/html 1264582305.793 1513 10.10.0.40 TCP_MISS/302 698 GET http://mail.yahoo.com/ MYDOMAIN\USERNAME DIRECT/69.147.112.160 text/html 1264582305.800 4 10.10.0.40 TCP_DENIED/407 7673 CONNECT login.yahoo.com:443 - NONE/- text/html 1264582305.810 4 10.10.0.40 TCP_DENIED/407 7883 CONNECT login.yahoo.com:443 - NONE/- text/html

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