RE: [squid-users] Automatic switching of squid to a second internet link?

Hi,

It seems that you need the iproute2 package, try finding out on the
www.lartc.org. I don't remember though, I guess theres a guide on how to
accomplish this. Hope that helps

Nats
-----Original Message-----
From: Danish Siddiqui [mailto:dsiddiqui@vertex.co.in]
Sent: Wednesday, July 04, 2007 3:37 PM
To: squid-users@squid-cache.org
Cc: Tek Bahadur Limbu
Subject: Re: [squid-users] Automatic switching of squid to a second internet
link?

Tek Bahadur Limbu wrote:
> Danish Siddiqui wrote:
>>
>> Hi,
>> Ive got squid proxy server running on a CentOS 4.4 machine. This proxy
>> server is connected to the internet through a Sonicwall PRO3060
>> firewall machine.
>>
>> We have got three different ISP lines, one of which is used by squid.
>> All the three lines terminate at the firewall. One of these links then
>> goes to the squid server.
>> Many a times it happens that the internet link on the squid line goes
>> down, because of which we have to switch the squid server on to one of
>> the remaining ISP lines.
>
> Hi Danish Siddiqui,
>
> When the 1st ISP goes down, does that mean that you actually have to
> switch the cable from your squid box to the 2nd or 3rd ISP link on
> your Sonicwall machine?
>
No, the only cable that is connected to the squid box is from the
Sonicwall firewall.
>>
>> I was planning a setup in which an extra NIC would be attached to the
>> squid server. This NIC would be connected to a different ISP line, so
>> that when one link goes down, the squid proxy server automatically
>> switches on to the next line, wherein the LAN users dont get to feel
>> the difference while browsing. Also, when the original link gets
>> restored, the squid server automatically switches back on to the
>> original link
>
> If your Sonicwall firewall and routing policy allows you to access all
> 3 ISPs lines from your Squid box, I think that you can use the
> "tcp_outgoing_address" parameter to switch to either the 2nd or 3rd
> ISP connection when the 1st ISP goes down.
>
> Of course, you must have a small script in Crontab to check for
> internet connectivity to your 1st ISP at regular intervals, say every
> 2 minutes.
>
How will the script go. Can you give me some pointers till the time I
look around for it.
> If the 1st ISP gets internet connectivity again, then let the script
> restore connectivity from the 2nd or 3rd ISP back to the 1st ISP again.
>
> But again, adding 2 extra NIC cards to your Squid box will provide you
> more control and fail over. In my opinion, it will be a very
> interesting option.
>
Seems interesting to me too
> If your Squid box is running on Linux with a kernel greater than
> 2.4.20, then you can apply traffic and routing rules.
Its running on a CentOS 4.4 with kernel 2.6.9-42.ELsmp
>
> Please see the following link:
>
> http://lartc.org/howto/lartc.rpdb.multiple-links.html
>
> This guys really seem to perform some kind of magic with advanced
> routing and traffic control!
>
>
>>
>> My current setup requires me to deny access to the squid server till
>> the time it is up again.
>
> I suppose that you can't access all 3 ISPs lines from your Squid box?
Ill have to go according to your suggestions. But at the moment the
squid box can access only 1 ISP line
>
>>
>> Is this setup possible? And if yes, can you please tell me how or
>> point me to the necessary resources.
>
> I definitely think it is possible. Let's wait and get more help and
> input from other experts and professionals from the Squid mailing list.
>
>
> Thanking you...
>
>>
>> Thanks
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>
>

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