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Posted to users@tomcat.apache.org by Stephen Charles Huey <st...@fastmail.fm> on 2005/01/24 19:15:05 UTC

Emergency: make Tomcat forward

I have Tomcat 4.1.27 on a Linux box at a particular public IP address,
and I want to make it forward ALL requests to a Tomcat on a Windows box
at another public IP address.  Over the weekend, we changed the DNS to
the Linux box, but now we need to roll back to the Windows box, and we
already changed the DNS through our ISP, and a lot of folks are hitting
the Windows box, but some people are still hitting the Linux one.  So,
we want to turn on the Tomcat on the Linux box and somehow send all
those folks to the Windows one.  

Is there any way to do this?  


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Re: Emergency: make Tomcat forward

Posted by Wouter Boers <wg...@gmail.com>.
Set up apache on the linux box and let it forward all request to the
windows box. The apache httpd documentation provides excelent help on
this subject.

In all fairness, a network administrator should have warned you that
this would happen. DNS changes are never instant but can take up to a
week to get propagated all over the world.

Wouter


On Mon, 24 Jan 2005 21:23:57 +0000, Graham Bleach
<gr...@darkskills.org.uk> wrote:
> On Mon, Jan 24, 2005 at 12:15:05PM -0600, Stephen Charles Huey wrote:
> > I have Tomcat 4.1.27 on a Linux box at a particular public IP address,
> > and I want to make it forward ALL requests to a Tomcat on a Windows box
> > at another public IP address.  Over the weekend, we changed the DNS to
> > the Linux box, but now we need to roll back to the Windows box, and we
> > already changed the DNS through our ISP, and a lot of folks are hitting
> > the Windows box, but some people are still hitting the Linux one.  So,
> > we want to turn on the Tomcat on the Linux box and somehow send all
> > those folks to the Windows one.
> >
> > Is there any way to do this?
> 
> This is completely offtopic.
> 
> Some ideas:
> 
> - If you only have one virtual host on the Windows box, then start a
> webserver on the Linux box and set it to redirect to the IP address of
> the windows machine.
> 
> - Start a proxy on the Linux box and have it hand all requests to the
> Windows box.
> 
> - Add some NAT rules to the linux box's netfliter rules to send all
> connections (depends on root access and relevant kernel modules being
> installed)
> 
> # very much untested and to be used at your own risk!
> cat /proc/sys/net/ipv4/ip_forward       # check what it's set to now
> echo 1 >/proc/sys/net/ipv4/ip_forward
> iptables -I PREROUTING -t nat -p tcp --dport 80 -d <linux ip> -j DNAT \
>     --to-destination <windows ip>
> 
> To revert back to previous state, write the previous value of
> /proc/sys/net/ipv4/ip_forward back to it and then replace the '-I' in
> the iptables command with a '-D'.
> 
> G
> --
> The average girl would rather have beauty than brains because she knows
> that the average man can see much better than he can think.
>         -- Ladies' Home Journal
> 
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> To unsubscribe, e-mail: tomcat-user-unsubscribe@jakarta.apache.org
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> 
> 


-- 
Regards, Wouter Boers
business: http://www.abcdarium.nl
personal: http://www.ikke.net

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Re: Emergency: make Tomcat forward

Posted by Graham Bleach <gr...@darkskills.org.uk>.
On Mon, Jan 24, 2005 at 12:15:05PM -0600, Stephen Charles Huey wrote:
> I have Tomcat 4.1.27 on a Linux box at a particular public IP address,
> and I want to make it forward ALL requests to a Tomcat on a Windows box
> at another public IP address.  Over the weekend, we changed the DNS to
> the Linux box, but now we need to roll back to the Windows box, and we
> already changed the DNS through our ISP, and a lot of folks are hitting
> the Windows box, but some people are still hitting the Linux one.  So,
> we want to turn on the Tomcat on the Linux box and somehow send all
> those folks to the Windows one.  
> 
> Is there any way to do this?  

This is completely offtopic.

Some ideas:

- If you only have one virtual host on the Windows box, then start a
webserver on the Linux box and set it to redirect to the IP address of
the windows machine.

- Start a proxy on the Linux box and have it hand all requests to the
Windows box.

- Add some NAT rules to the linux box's netfliter rules to send all
connections (depends on root access and relevant kernel modules being
installed)

# very much untested and to be used at your own risk!
cat /proc/sys/net/ipv4/ip_forward       # check what it's set to now
echo 1 >/proc/sys/net/ipv4/ip_forward
iptables -I PREROUTING -t nat -p tcp --dport 80 -d <linux ip> -j DNAT \
    --to-destination <windows ip>

To revert back to previous state, write the previous value of
/proc/sys/net/ipv4/ip_forward back to it and then replace the '-I' in
the iptables command with a '-D'.

G
-- 
The average girl would rather have beauty than brains because she knows
that the average man can see much better than he can think.
        -- Ladies' Home Journal

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Re: Emergency: make Tomcat forward

Posted by Tim Funk <fu...@joedog.org>.
If you can use tomcat5 - look at the balancer webapp.

-Tim

Stephen Charles Huey wrote:

> I have Tomcat 4.1.27 on a Linux box at a particular public IP address,
> and I want to make it forward ALL requests to a Tomcat on a Windows box
> at another public IP address.  Over the weekend, we changed the DNS to
> the Linux box, but now we need to roll back to the Windows box, and we
> already changed the DNS through our ISP, and a lot of folks are hitting
> the Windows box, but some people are still hitting the Linux one.  So,
> we want to turn on the Tomcat on the Linux box and somehow send all
> those folks to the Windows one.  
> 
> Is there any way to do this?  
> 

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