[Dshield] OK, well I didn't expect DNS to cause that furry.

Richard Roy RoyR at justicetrax.com
Mon Sep 8 15:33:04 GMT 2003


Sorry for causing such a stir.
The debate was an interresting read.  I did not re-enter the topic as I,
shame on me, had a life away from the network, this weekend.  My
Daughters' birthday! (yep 2 of 'em) [insert proud daddy smile here]  I
digress.

I did not, in any way wish to cause such a stir.  I simply needed to
settle a dispute with a coworker and thought of the list as a great
place to get an answer.  Thankfully I learned quite a bit.  To all of
you who responded (even those who flamed (you know who you are)) thanks.
To those who responded off list, again thanks. 

The discussion has made me wonder if the RFC's need updating, etc.  I
don't much follow the logic of not having a receiving mail server in DNS
if you are going to send.  Quite frankly, that won't happen with any of
my customers, this much I know based upon who they are.  Some of you
have attempted to address that, but I still liken it to a person who
sends a ton of postcards in the big blue post boxes, yet does not ever
wish to receive any response.  I don't care to read them.

My co-worker made some claims and I disagreed.  It is likely that we
were both correct.  My observations were different from his.  He stated
that any system could send email to any mail server.  While that may be
true in a purist sense, reality is somewhat different.

To quote from an off list response.
"He claims that if he is at home on say verizon or some isp, that when
he clicks send, his machine checks dns, then connects to the mx record,
then delivers the mail.  I didn't think that was how it worked, why then
would you need to fill in outgoing (smtp) mail server info to send mail
right?  I told him I believe that what happens is that when he clicks
end, it checks for the outgoing server address, then that server
connects to my mail server to deliver the mail.  Am I wrong? Curious."

This was the jist of what I was looking to have answered.  I am sorry if
I did not originally pose the question correctly.  He had claimed that
he was sending the mail directly from his system.  While some ISP's
might not block mail outbound from their domain from any system, I was
willing to bet the majority allowed only a few servers to send and not
just any client.  Oh well, made for interresting reading none the less.

Again, thanks to all for their responses.  As usual the list shows the
breadth of experience, knowledge, and understanding I have come to rely
upon.  You guys and gals ROCK!

Richard Roy
Network Administrator
JusticeTrax Inc
602-938-0059 x102
royr at justicetrax.com




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