Date: Sun, 22 Jun 2003 18:18:06 +0800 From: "Paul Hamilton" <paul@bdug.org.au> To: "Andrew Thomson" <ajthomson@optushome.com.au> Cc: Freebsd-Questions <freebsd-questions@freebsd.org> Subject: RE: Transparent Proxy going astray Message-ID: <AGEHIFHGNEMPFNCPLONMCEKIEMAA.paul@bdug.org.au> In-Reply-To: <20030621054919.GB79173@athomson.prv.au.itouchnet.net>
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Nope! :-( Yes the gateway server (192.168.0.10), runs IPFW2, squid, ppp etc. I added the skip rule as you suggested. I see traffic getting to rule 60, but since I don't know of a way to tcpdump on lo0 traffic, I don't know how to troubleshoot further. Oh yes, it looks like squid logs do register a miss (after a long time out): 1056276094.519 10998 192.168.0.2 TCP_MISS/000 0 GET http://www.google.com/ I checked and made sure that the squid ACL is allowing 192.168.0.0 and 127.0.0.1 traffic through. Also what is generating this traffic (via tcpdump on the inside NIC): 17:50:51.073150 192.168.0.2.4339 > 203.10.1.17.53: 1355+ A? www.google.com. (32) 17:50:51.375673 203.10.1.17.53 > 192.168.0.2.4339: 1355 1/4/4 A 216.239.39.99 (184) 17:50:51.378720 192.168.0.2.4340 > 216.239.39.99.80: S 673769954:673769954(0) win 16384 <mss 1460,nop,nop,sackOK> (DF) 17:50:51.378774 216.239.39.99.80 > 192.168.0.2.4340: R 0:0(0) ack 673769955 win 0 17:50:51.814743 192.168.0.2.4340 > 216.239.39.99.80: S 673769954:673769954(0) win 16384 <mss 1460,nop,nop,sackOK> (DF) 17:50:51.814794 216.239.39.99.80 > 192.168.0.2.4340: R 0:0(0) ack 1 win 0 17:50:52.315527 192.168.0.2.4340 > 216.239.39.99.80: S 673769954:673769954(0) win 16384 <mss 1460,nop,nop,sackOK> (DF) 17:50:52.315579 216.239.39.99.80 > 192.168.0.2.4340: R 0:0(0) ack 1 win 0 Hmmm, hang on, if the above is from the inside NIC (tun0 shows only the DNS lookup), why am I seeing the 216.239.39.99:80 traffic? Is squid somehow directing it back inside, instead of out via tun0? Is this a squid config problem? By the way, examining the packets via Ethereal, it looks like there is no data in that packets. I know this is a standard setup, I'm just perplexed on where I have gone wrong (and why I can't troubleshoot it further) Cheers, Paul Hamilton -----Original Message----- From: owner-freebsd-questions@freebsd.org [mailto:owner-freebsd-questions@freebsd.org]On Behalf Of Andrew Thomson Sent: Saturday, 21 June 2003 1:49 PM To: Freebsd-Questions Subject: Re: Transparent Proxy going astray Paul, You'd probably have noticed a few posts from me on this very subject. The good news is I did end up getting it all working.. but there were definitely a few hurdles in the way. I assume your firewall is also running the squid proxy? For some reason, I got away with just putting rule 60 in! I also added a dst port of 80 so just my http traffic got forwarded. If this is your firewall, then you'd probably want to change rule 50 to something like: skipto 70 tcp from 192.168.0.10 to any 192.168.0.10 is your firewall?? >From my understanding, an add rule will stop moving through the ruleset however you still need your requests to go through nat etc etc.. Let me know how you get on. You can be restassured that it is possible. I have now setup transparent proxies with the proxy running on the firewall and also with the proxy running on another box. I've also used 4.7 and 5.0 in seperate instances sucessfully too! good luck, ajt. On Sat, Jun 21, 2003 at 01:34:17PM +0800, Paul Hamilton wrote: > Hi all, > > I have watched/lurked on this list for sometime now, and see a Transparent > Proxy question every now or then. None of them have answered my problem. I > give it a bash every now and then to see if I will trip over the answer. It > hasn't worked, so I will try this list again. > > I run FreeBSD 4.8 on the gateway, Squid Cache: Version 2.4.STABLE4 > > Squid.conf has the required lines: > > http_port 8080 > httpd_accel_port 80 > httpd_accel_host virtual > httpd_accel_with_proxy on > httpd_accel_uses_host_header on > > and the required ipfw2 firewall rules: > > 00050 271 27520 allow tcp from 192.168.0.10 to any > 00060 3 144 fwd 127.0.0.1,8080 tcp from any to any dst-port > 80 > > Interestingly enough when watching the ip traffic on the gateway, I see this > on my inside NIC: > > 08:27:18.735861 192.168.0.2.3276 > 203.10.1.17.53: 1093+ A? > www.google.com.au. (35) > 08:27:18.922217 203.10.1.17.53 > 192.168.0.2.3276: 1093 2/4/4 > CNAME[|domain] > 08:27:18.923667 192.168.0.2.3277 > 216.239.39.99.80: S > 813553086:813553086(0) win 16384 <mss 1460,nop,nop,sackOK> (DF) > 08:27:18.923722 216.239.39.99.80 > 192.168.0.2.3277: R 0:0(0) ack 813553087 > win 0 > 08:27:19.397657 192.168.0.2.3277 > 216.239.39.99.80: S > 813553086:813553086(0) win 16384 <mss 1460,nop,nop,sackOK> (DF) > 08:27:19.397697 216.239.39.99.80 > 192.168.0.2.3277: R 0:0(0) ack 1 win 0 > 08:27:19.906095 192.168.0.2.3277 > 216.239.39.99.80: S > 813553086:813553086(0) win 16384 <mss 1460,nop,nop,sackOK> (DF) > 08:27:19.906153 216.239.39.99.80 > 192.168.0.2.3277: R 0:0(0) ack 1 win 0 > > > and this on my outside NIC: > > 08:27:18.736970 202.72.147.43.3276 > 203.10.1.17.53: 1093+ A? > www.google.com.au. (35) > 08:27:18.922026 203.10.1.17.53 > 202.72.147.43.3276: 1093 2/4/4 CNAME > www.google.com., (215) > > The cache_access.log doesn't show any traffic, yet (something) is pretending > to be the google website, as there is a reply from 216.239.39.99.80. I have > tried to run tcpdump -ni lo0 but there isn't any traffic. > > Should I be able to see traffic on lo0? > > Any thoughts on what I am missing? > > Cheers, > > Paul Hamilton > > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org" > _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org"
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