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Re: Why are so many DNS requests necessary at all?

2005-04-01 03:50:55
"Graham Murray" opined:


"Chris Haynes" <chris(_at_)harvington(_dot_)org(_dot_)uk> writes:

In simple cases, that need only involve a single look-up.  The multiple
look-ups
usually arise if you have a Mail From domain who uses a different domain's
servers to send its mail. Almost all small/medium business and 'vanity'
domains
are in this situation. They use an ISPs outbound mail servers.

This has often been stated, and I have wondered why.

<snip>

So it seems to me that, for systems which have 'always on' connections
to the internet, the benefits of a domain running its own mail server
far outweigh the convenience of letting the ISP do all the work.



Obviously, it's a business decision. I can think of three factors:

1) Skills and business priorities. Not all small businesses have the skills /
inclination / time to run their own mail services.

2) Not all 'always on' connections have a long-term guarantee about the IP
address they are allocated.

3) Reliability. Few SMEs want the expense and hassle of duplicate connections,
servers, etc. to be sure to be offering an inbound service with a high enough
availability.



Chris Haynes