[squid-users] RE: WCCP issues with Centos 6.3 and Cisco 2901

From: Jordan Dalley <jdalley_at_tsv.catholic.edu.au>
Date: Mon, 23 Sep 2013 23:31:29 +0000

Thanks for your reply Bob,

I tried what you said - completely removed any ifcfg-gre0 config and simply ran the commands:

ifconfig gre0 inet 1.1.1.1 netmask 255.255.255.0 up
iptables -F -t nat
iptables -t nat -A PREROUTING -i gre0 -p tcp -m tcp --dport 80 -j DNAT --to-destination 10.112.4.4:3127

On the router side (I had to modify your acl's a bit)

ip access-list standard wccp-servers
permit host 10.112.4.4
ip access-list extended wccp-traffic
permit tcp 10.114.32.0 0.0.7.255 any eq www

ip wccp web-cache redirect-list wccp-traffic group-list wccp-servers

Upon inspection, I can see the router forwarding packets through the gre tunnel:

[root_at_tsv-squid1 ~]# tcpdump -i gre0
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on gre0, link-type LINUX_SLL (Linux cooked), capture size 65535 bytes
20:40:04.370754 IP 10.114.32.51.62007 > 190.93.248.164.http: Flags [S], seq 2779756886, win 8192, options [mss 1460,nop,wscale 2,nop,nop,sackOK], length 0
20:40:04.370861 IP 10.114.32.51.62008 > 190.93.248.164.http: Flags [S], seq 1665803222, win 8192, options [mss 1460,nop,wscale 2,nop,nop,sackOK], length 0
20:40:07.381696 IP 10.114.32.51.62007 > 190.93.248.164.http: Flags [S], seq 2779756886, win 8192, options [mss 1460,nop,wscale 2,nop,nop,sackOK], length 0
20:40:07.381779 IP 10.114.32.51.62008 > 190.93.248.164.http: Flags [S], seq 1665803222, win 8192, options [mss 1460,nop,wscale 2,nop,nop,sackOK], length 0
20:40:13.387792 IP 10.114.32.51.62007 > 190.93.248.164.http: Flags [S], seq 2779756886, win 8192, options [mss 1460,nop,nop,sackOK], length 0
20:40:13.387812 IP 10.114.32.51.62008 > 190.93.248.164.http: Flags [S], seq 1665803222, win 8192, options [mss 1460,nop,nop,sackOK], length 0

Here's the weird thing..

[root_at_tsv-squid1 ~]# ifconfig gre0
gre0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-82-12-00-00-00-00-00-00-00-00
          inet addr:1.1.1.1 Mask:255.255.255.0
          UP RUNNING NOARP MTU:1476 Metric:1
          RX packets:143 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:7136 (6.9 KiB) TX bytes:0 (0.0 b)

Note my GRE tunnel is not transmitting, only receiving.

I can confirm, ip forwarding is enabled.

[root_at_tsv-squid1 ~]# cat /proc/sys/net/ipv4/ip_forward
1
[root_at_tsv-squid1 ~]#

Cheers,
J.

-----Original Message-----
From: Luderitz Bob [mailto:Bob.Luderitz_at_NiproGlassAmericas.com]
Sent: Tuesday, 24 September 2013 1:38 AM
To: squid-users_at_squid-cache.org
Subject: [squid-users] RE: WCCP issues with Centos 6.3 and Cisco 2901

        Hey Jordan, I am running a similar config with wccp and CentOS 6.3 with Cisco routers.

        Your config looks close to what I have but I use the built-in gre0 tunnel so don't have the interface explicitly setup just have it in rc.local like this:
        ifconfig gre0 inet 1.2.3.4 netmask 255.255.255.0 up
        echo 1 > /proc/sys/net/ipv4/ip_forward
        (same iptables statement as you have)
        iptables -F -t nat
        iptables -t nat -A PREROUTING -i gre0 -p tcp -m tcp --dport 80 -j DNAT --to-destination 10.80.166.227:3127

        From the router - I did not set the config up but have to documentation and have these additional statements defined to force http traffic to the squid - 166.227)
        access-list wccp-servers extended permit ip host 10.80.166.227 any
        access-list wccp-traffic extended permit tcp object-group DM_INLINE_NETWORK_7 any eq www
        wccp web-cache redirect-list wccp-traffic group-list wccp-servers
                
        hope this helps....

-----Original Message-----
From: Jordan Dalley [mailto:jdalley_at_tsv.catholic.edu.au]
Sent: Monday, September 23, 2013 6:17 AM
To:
Subject: [squid-users] WCCP issues with Centos 6.3 and Cisco 2901

Hi Squid community,

I have an issue whereby I am just struggling to find out why it wont work.

I have trawled through multiple forums, howto's, faq's etc but no matter what I do, I cannot get it to work properly.

Here is what I have done so far:

Router IP: 10.114.3.34
Squid IP: 10.112.4.4
WAN Subnet: 10.112.0.0 / 255.252.0.0

Squid Config:

http_port 3127 intercept
wccp2_router 10.114.3.34
wccp2_forwarding_method gre
wccp2_return_method gre
wccp2_service standard 0

Confirm I can access and use port 3127 directly without issue from any location in the WAN.

Router Config:

ip wccp web-cache
interface G0/1
!Inside interface
ip wccp web-cache redirect in

Added to sysctl.conf:

# Controls IP packet forwarding
net.ipv4.ip_forward = 1

# Controls source route verification
net.ipv4.conf.default.rp_filter = 0
net.ipv4.conf.eth0.rp_filter = 0
net.ipv4.conf.eth0.ip_filter = 0
net.ipv4.conf.gre0.rp_filter = 0
net.ipv4.conf.gre0.ip_filter = 0

Added to /etc/sysconfig/network-scripts/ifcfg-gre0

DEVICE=gre0
BOOTPROTO=static
IPADDR=127.0.0.2
NETMASK=255.255.255.0
ONBOOT=YES
IPV6INIT=NO

Linux Configuration:

modprobe ip_gre
ifup gre0
iptables -t nat -F
iptables -t nat -A PREROUTING -i gre0 -p tcp -m tcp --dport 80 -j DNAT --to-destination 10.112.4.4:3127

If, I then do a tcpdump -i gre0 I can see packets flowing through this interface with destination port 80. Unfortunately it seems as if they are somehow not being natted to the squid server.

I've tried different varying methods of doing this, but none of them seem to work.

Does anyone have any ideas?

Regards,
Jordan.

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Received on Mon Sep 23 2013 - 23:32:23 MDT

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