smtp load balancer???

Sean Embry sean at NISD.NET
Wed Dec 7 20:49:13 GMT 2005

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> The issue is that when a toaster goes down or needs to be taken off
> line, simply removing it from DNS is not enough. Those %#$^& windows
> machines refuse to update their DNS when it expires. If I have a HD
> and want to take a server off line for repair, my windows clients begin
> to fail connections. The current solution is for me to drive to the NOC
> (50 miles) at 3am and do the work. If the work cannot be completed by
> 7am, we tell our dialup clients to reboot their PC, and our commercial
> clients to flush their DNS cache when they call, which they will.
> I have a toaster removed from DNS now for over two weeks awaiting an OS
> upgrade, and it is still handling thousands of messages a day. A good
> load balancer will solve that problem.
On the sick server, alias in a reserve IP address (so you can still get
to it remotely),
remove the old IP address, reboot if you have to. (I'm not a windows
On a working server, add the sick machine's IP address as an alias to the
If the sick server has crashed and isn't on line, just add it's IP to
another server and kill the port on the down server.
Using Cisco switches, you may have to flush the arp cache. On some of my
switches using fault flexable service
provision, I use a five second arp cache timeout. The Network guys hate
that, they say it adds a lot of load to the switch.
Sean Embry
Systems/Database Administrator
(210) 397-8790

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