Re: Fwd: [squid-users] URL redirection in offline mode

On Wed, Oct 6, 2010 at 8:52 PM, Amos Jeffries <squid3_at_treenet.co.nz> wrote:
> On 07/10/10 00:53, mohd hafiz wrote:
>>
>> On Wed, Oct 6, 2010 at 6:54 PM, Amos Jeffries<squid3_at_treenet.co.nz>
>>  wrote:
>>>
>>> On 06/10/10 22:55, mohd hafiz wrote:
>>>>
>>>> ---------- Forwarded message ----------
>>>> From: mohd hafiz<bmhafiz_at_gmail.com>
>>>> Date: Wed, Oct 6, 2010 at 5:17 PM
>>>> Subject: Re: [squid-users] URL redirection in offline mode
>>>> To: Amos Jeffries<squid3_at_treenet.co.nz>
>>>>
>>>>
>>>> thanks for fast respon,
>>>>
>>>> my squid will have to operate in network up and down. it will just do
>>>> normal operation when the network is up. When the network is down,
>>>> squid will intercept all request from client and point it to local
>>>> server. i write a perl script to do the redirection.
>>>
>>> No need for that. redirect is automatic by prefer_direct. The local
>>> server
>>> just needs to accept the random domains passed to it by Squid.
>>>
>> you means i did not need the perl script? i used the perl script in
>> url_rewrite program /etc/squid/redirect.pl.
>>
>
> Yes I mean you don't need to do that. See below.
>
>>
>>>> i have configure my cache_peer to:
>>>>
>>>> cache_peer example.com 3128 3130 default
>>>
>>> example.com being your "local server". Is that another proxy or a web
>>> server? The answer will determine whether you use port 3128/3130 or 80/0.
>>>
>> example.com is my web server
>
> Then you need to use:
>   cache_peer example.com 80 0 default
>
i miss the type(parent, sibling, multicast) after hostname. can i
write cache_peer example.com parent 80 0 default?

>>>>
>>>> and enable
>>>>
>>>> prefer_direct on
>>>>
>>>> but the browser still tried to reach the internet. it takes a few
>>>> minutes to resolve to my local page. any advised?
>>>
>>> Are you doing WCCP, NAT interception or transparent proxy?
>>>
>> i'm doing transparent proxy
>>
>>> If yes,
>>>  the browser will be attempting and failing its own DNS to go direct to
>>> the
>>> Internet Squid cannot help here. Connectivity failover with a proxy is
>>> not
>>> easily compatible with interception.
>>>
>> is squid cannot function when the network is down? i know that squid
>
> Due to transparent proxy, the problem is not in Squid.
>
>  Right at the very start the web browser does its own DNS thinking it has to
> contact the Internet itself. This first DNS fails and the browser presents
> the "unable to resolve" page. The request never gets near Squid to pass to
> the peer.
>
> If you have a local resolver which is still relaying results to the browser
> the request will possibly get to Squid where things continue as desired. Any
> DNS delay will be doubled or tripled.
>
>
> Configure the browser to pass requests directly to the proxy. The browser
> will then start by passing the request to Squid. From there your Squid
> failover config has control.
>
Does i need to configure each browser to pass request to squid? Can it
be done by the iptables at the server side. i want it transparent to
the user.
>
>>
>> will do a dns lookup at the startup. squid will not start if it fails
>> dns lookup. i have tried to disable the internal dns lookup and still
>> problem exists. is there any way to solve this?
>
> Disabling the internal DNS resolver only switches to using an old slower
> external resolver process.
>
> Squid requires DNS when it has to process a squid.conf entry from a name to
> an IP. Such as names in src/dst ACLs. Using IP addresses there will help
> avoiding DNS on startup.
i'm using ip for my acl setup. for example : acl lan src
129.34.4.0/32; is there other place i need to use IP adress to avoid
DNS on startup? or how can i avoiding DNS on startup?

>
> Older Squid needed the -D command line option to prevent tests of the
> configured nameservers. And visible_hostname to prevent looking up its
> hostname rDNS.
>  Newer Squid have dropped the -D and related tests, and their
> visible_hostname will failover to "localhost" instead of stopping.
>
>
>> i also do a setup as below:
>> i have write a shell script to ping the network and write the status
>> to a text file. the perl script will read the text file
>> and do the redirection based on the output from the text file.
>
> Sending a packet (ping echo, or TCP open connection) to somewhere outside
> will produce a success/fail result. The NIC card whose cable got
> disconnected produces a ICMP message to notify that another route must be
> used. Squid probes and receives these for each and every request.
>
> It's identical to what your perl script and text files do, but happens
> automatically within nanoseconds of any network change.
>
> Amos
> --
> Please be using
>  Current Stable Squid 2.7.STABLE9 or 3.1.8
>  Beta testers wanted for 3.2.0.2
>
thanks
Received on Thu Oct 07 2010 - 08:02:41 MDT