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HeadSpinning
MNSi Internet

join:2005-05-29
Windsor, ON
kudos:5
reply to 80289148

Re: [Cable] Reason for no Static IP Availability for Cable Inter

said by 80289148:

said by UnixMan:

quote:
This is incorrect. I have ran a mail server for 10 years on a non-static IP without issues.
That was correct. And this is why

Sorry I don't click links. And I am running one so I know it works.

I'll click it for you:

Why mail to and from a dynamic DNS Host does not work reliably

No matter what they tell you, mail to and from dynamic DNS Hosts does not work reliably.
At least without TLS it isn't. Here's how it works with TLS: »www.thalmann.de/postfix-dialup.html

Receiving mail

Why receiving mail does not work reliably:
If you register your dynamic IP in a dynamic DNS provider like dyndns.org, your dyndns.org hostname is assigned your dynamic IP
If your machine loses the internet connectivity, then the hostname will still point to your former IP.
Now somebody else gets your former IP:
The computer has nothing listening on port 25:
No problem!
The computer has a properly setup MTA on port 25:
Your mail will be bounced! This is bad.
The computer has an open relay MTA on port 25:
Your mail will be relayed by this machine.
The computer has a blackhole MTA.
Your mail will be lost! This is bad.
Sending mail

Why sending mail does not work reliably:
Nowadays, many providers don't accept mail from dynamically assigned IP pools (like your dialup / DSL IP range). This means you must use the relayhost of your ISP.
--
MNSi Internet - »www.mnsi.net


Inssomniak
The Glitch
Premium
join:2005-04-06
Cayuga, ON
kudos:2
^^ Everything HeadSpinning said..