[wellylug] Meeting idea

[Don Jones]

One thing to be aware of if you wish to run your own mailserver, you will need a static IP and a domain name that you have enough control of to add MX records. This pretty much limits home users to Paradise Cable which use statics. You could probably use a dynamic dns service but this is not an ideal solution, and never having used one I dont know that they do MX records. That said MX records are not totally essential most SMTP implementations will attempt to connect to port 25 domain.com if it has no MX record. For those on xDSL static IPs and  the ability to point dns records at that address are usually reserved for business customers (Jetstream600 Jetstream1200 etc.) it would also mean that your address would have to be somthing like you at your-choice-of-subdomain.your-dynamic-dns-provider-her.com
 
Another issue is reliability - broadband is not terribly reliable compared to ethernet (citylink united networks etc.) or frame relay, cable in my experience is more robust than xDSL but both are prone to outages. This is an issue if you are running a mailserver, if the link is down the sending mailserver will deferr and place the email in the queue and try again later. Eventually it'll send one of those Mail Delivery Subsystem <MAILER-DAEMON> type messages to the sender saying the mailserver is not avalible. The best way to avoid this is to have a secondary mx, this would be a server that is configured to relay for your domain, so when someone tries to send you mail it looks up the mx records, tries the primary server, gets no response, tries the secondary, the secondary then places the mail in its queue and delivers it when the primary comes back up. The secondary would be configured to queue mail for longer than average. All this is of course overkill for a small server t!
ho.

Most home users I think wouldnt want this type of setup, if you have a bunch of isp and webmail accounts to aggregate you need to be looking at something like fetchmail and webmail download scripts.

If you are intrested in the mx records stuff try out this command:

$host -t mx some-domain.com

you may see only one record or more, records have different priorities, the sending server will try the lowest priority server first.

If you want to see what software a server is running try this (can use with netcat aswell if you have it)

telnet mailserver.domain.com 25

if there is a mailserver listening you will get a SMTP banner something like this:

220 mailserver.domain.com (mailserver version)

you can then send the server commands if you feel like it, like this:

HELO foo.com
250 blah.bar.co.nz Hello foo.com [23.79.16.11], pleased to meet you
MAIL FROM: don at foo.com
250 2.1.0 don at foo.com... Sender ok
RCPT TO: d.jones at bar.co.nz
250 2.1.5 d.jones at bar.co.nz... Recipient ok
DATA
354 Enter mail, end with "." on a line by itself
test
.
250 2.0.0 h1Q6CdT12651 Message accepted for delivery
QUIT
221 2.0.0 blah.bar.co.nz closing connection

if you want to exit before this use CTRL-] telnet> quit

hope someone finds this intresting

Don Jones

"The rules of proprietary software break down cooperation between programmers separated by company boundaries, even when such cooperation can be of benefit to both organizations."
-- 
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