[squid-users] Squid on separate box and it can't see packets

[Eliezer Croitoru]

Hey,

There are couple missing pieces(in my eyes) in order to understand the picture.
Is this squid box a router or just a proxy?
What tcpdump command did you ran?
What is the networks that are involved?
What is the gateway and dhcp for this network?
If the client is a linux box then we need the output of:
$ ifconfig
$ route -n 
Or
$ ip route

Thanks,
Eliezer

----
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Email: eliezer at ngtech.co.il


From: squid-users [mailto:squid-users-bounces at lists.squid-cache.org] On Behalf Of John Pearson
Sent: Tuesday, February 14, 2017 8:25 AM
To: Squid Users <squid-users at lists.squid-cache.org>
Subject: [squid-users] Squid on separate box and it can't see packets

Hi all,
I have squid on a separate box on my network with ip address 192.168.1.2

In squid.conf I have:

http_port http://0.0.0.0:3128
http_port http://0.0.0.0:3129 intercept

-------

On squid box:

$ sudo netstat -lnp | grep squid
tcp        0      0 http://0.0.0.0:3128            0.0.0.0:*               LISTEN      2639/(squid-1)
tcp        0      0 http://0.0.0.0:3129            0.0.0.0:*               LISTEN      2639/(squid-1)
udp        0      0 http://0.0.0.0:37444           0.0.0.0:*                           2639/(squid-1)
udp6       0      0 :::41465                :::*                                2639/(squid-1)

-------

I followed this example: http://wiki.squid-cache.org/ConfigExamples/Intercept/LinuxRedirect

iptables:

# your proxy IP
SQUIDIP=192.168.1.2

# your proxy listening port
SQUIDPORT=3129


iptables -t nat -A PREROUTING -s $SQUIDIP -p tcp --dport 80 -j ACCEPT
iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-port $SQUIDPORT
iptables -t nat -A POSTROUTING -j MASQUERADE
iptables -t mangle -A PREROUTING -p tcp --dport $SQUIDPORT -j DROP

------

I am redirecting port 80 packets on my router to squid box

On one of the clients: 192.168.1.8, I am running
wget -v --bind-address=192.168.1.8 http://squid-cache.org:80

On squid box, I am running tcpdump and I am able to see those packets:

22:09:58.962316 IP 192.168.1.8.52219 > lists.squid-cache.org.http: Flags [S], seq 1999822717, win 29200, options [mss 1460,sackOK,TS val 26932460 ecr 0,nop,wscale 7], length 0
22:09:59.958994 IP 192.168.1.8.52219 > lists.squid-cache.org.http: Flags [S], seq 1999822717, win 29200, options [mss 1460,sackOK,TS val 26932560 ecr 0,nop,wscale 7], length 0
22:10:01.958981 IP 192.168.1.8.52219 > lists.squid-cache.org.http: Flags [S], seq 1999822717, win 29200, options [mss 1460,sackOK,TS val 26932760 ecr 0,nop,wscale 7], length 0

But squid is not seeing them. Squid log is empty.

Need advice. Thanks!