[kwlug-disc] Testing a mail port

[Khalid Baheyeldin]

For dig, you don't need a tutorial. It is just a fancier nslookup. The
man pages suffice here.

Learning the underlying DNS/Whois is what matters (e.g. A record is
for hosts IPv4, AAAA is IPv6, MX is mail servers, TXT is SPF, CNAME is
host aliased to other hosts, ...etc.)

As for nc, it is a generic network tool. The Digital Oceans tutorial is good

https://www.digitalocean.com/community/tutorials/how-to-use-netcat-to-establish-and-test-tcp-and-udp-connections-on-a-vps

And some tricks here

http://www.thegeekstuff.com/2012/04/nc-command-examples/

You do not need nc for basic mail server troubleshooting since telnet
does the same thing. Again, what is important is learning the
underlying mail server protocol is what matters, not the tool that you
will be sending those command from.

The RFC for SMTP is here
http://www.ietf.org/rfc/rfc2821.txt

As usual with RFCs it is dense and terse.

The gist of it is here:

http://www.tutorialspoint.com/internet_technologies/e_mail_protocols.htm

Remember that this is for plain text, which has been the case for
decades, but now many servers use encrypted connections, so not as
easy to simulate using telnet/nc.

On Thu, Mar 10, 2016 at 8:38 AM, Joseph Wennechuk
<youcanreachmehere at hotmail.com> wrote:
> So through all of this I learned that I need to brush up on two commands
> that seem very useful. I need to hone my skills with nc, and dig. They both
> seem very useful. Has there been a presentation about these?
>
>
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> kwlug-disc mailing list
> kwlug-disc at kwlug.org
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>



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