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Re: Alternative to BGP-4 for multihoming?

  • From: Ryan O`Connell
  • Date: Sun Mar 12 16:20:32 2000

On 12-Mar-2000 Peter A. van Oene wrote:
> F5's 3DNS will accomplish the same.  The redundancy is provide via DNS as
> opposed to having to worry about network advertisements via BGP4.
> Essentially, the 3DNS box assumes the DNS entry for the site for which the
> customer requires multihoming and it intelligently balances traffic amongst
> any geographically disparate sites.  This allows for high availability. 

If you use 3DNS make sure you're able to put up with a lot of abuse complaints
from other sites. It queries port 53 TCP (Domain) on systems to figure out the
"best" site to serve data from using the RTT. Worst case, if you've got a
paranoid ISP, you might even lose connectivity altogether.

I can't see why the software needs to use 53/TCP - I'd have thought 53/UDP or
ICMP echos would be less intrusive. Apparently it tries a domain XFER for some
reason, although no sign of this in my logs. Can't see why doing an xfer would
help load balancing decisions.

A certain very, very, very, very, very large US software/OS company uses 3DNS
and when I complained about a runaway port 53 scan against my systems (Which
looks for all the world like some sort of DoS attack or probe) the security/
abuse guy I ended up was rather less than impressed with the 3DNS system. I
got the impression they frequently get complaints about it.

Ryan O'Connell - <[email protected]>

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You can dance, you can jive, having the time of your life 
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