[squid-users] unable to bypass AUP page with local servers

From: Johnson, S <sjohnson_at_edina.k12.mn.us>
Date: Tue, 20 Apr 2010 10:23:32 -0500

Hello,

 I've got a weird issue that I've been finding off an on. I can finally
duplicate it regularly now. I'm working with a "public" network that
we've separated from the local network. We have web resources that are
on the external side of the squid box.

This is what our network looks like:

--------public network 65.80.133.x--------
   | |
   | public network
firewall---(nat)DMZ (192.168.80.x/23)
   | (192.168.2.0/24)
   | (web servers)
   |
   |
private network
(10.x.x.x)
 The squid server here is configured with an AUP page with a click
through to continue to the site they originally were trying to get to.
Any page outside of our network altogether works great; they get the AUP
and the click through it. However, if they try to access the local web
server which shares the same external subnet as the squid server then I
cannot click past the AUP.

 To make this a little more complex, I'm attempting to do this through
transparent proxy. I've also got DNS configured to provide a WPAD file.
If I use the autoproxy config in the browser then it works just fine
(which is why it was working for me). Once I turn this off in the
browser I once again cannot get to the local web server but other
outside sites work just fine. I don't see any hits in the log if I try
to browse the local web server which makes me believe that the traffic
isn't even hitting the proxy. However, it should since there are no
local routes on the workstation that would do otherwise. It's like the
proxy server isn't picking up the packets at all...

 Oh one more weird thing... if I set myweb in the acl below at the top
of the ACL list then I'm able to get to the local servers but the AUP
page never shows if their homepage is set to the local web server. I
guess I would expect this behavior since I've never denied the session.
I've tried moving the myweb acl around the whole list but I don't get
any other results...

This is my config:

# TAG: acl
#Recommended minimum configuration:
acl manager proto cache_object
acl localhost src 127.0.0.1/32
acl to_localhost dst 127.0.0.0/8
acl to_localbox dst 192.168.80.5/32
acl myweb dst 64.80.132.1/32

follow_x_forwarded_for allow localhost
acl_uses_indirect_client on
delay_pool_uses_indirect_client on
log_uses_indirect_client on

external_acl_type session ttl=10 children=1 negative_ttl=0
concurrency=200 %SRC /usr/lib/squid/squid_session -t 1800

acl session external session

acl localnet src 192.168.80.0/23 # 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

# TAG: http_access
http_access allow to_localbox
deny_info http://192.168.80.5/index.php?url=%s session
#http_access allow myweb #trying different locations for the session to
be set
http_access deny !Safe_portshttp_access allow session
http_access allow SSL_ports
http_access allow CONNECT SSL_ports
http_access deny !session
http_access allow myweb
http_access deny !Safe_ports

http_access deny all

http_port 3128 transparent
Received on Tue Apr 20 2010 - 15:23:34 MDT

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