North American Network Operators Group

Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

Re: Selection of Appropriate Local SMTP Relay

  • From: Forrest W. Christian
  • Date: Tue Jan 11 00:46:03 2000

I'm going to make a pitch for the IP-address based method.

Specifically, if you have a set of well known IP addresses for common
services, thus something like: - Primary DNS - Secondary DNS - SMTP Mail - Time Server

You could very easily support this in ANY network.  No additional
HW/software required.


config> ip route dns.ser.ver.addr
config> ip route smtp.ser.ver.addr

and so on.

You then add an alias on the loopback interface for the "well known"
address and make sure your dns/smtp daemon binds to it.

Easy to implement, easy to explain, no additional coding changes required,
although it would be nice to have stuff ship with these pre-configured.

All that you need is a chunk of address space reserved for this and a list
of services, each assigned to an address.

I think that, barring the need to find/get the IP address block, it should
take only a day or so to build an appropriate list of services.

The main DNS detractor that I see is figuring out how to hand out DNS
server numbers in a CONSISTENT, RELIABLE fashion for roaming users.

Remember, that the purpose of this is for someone to be able to find the
"correct" server to provide the services which a roaming user will find at
different locations depending on where they are dialing in, thus, a
config for a user would be:

DNS Servers - varies by location
SMTP server - varies by location
pop3/imap server - always home isp
time server - varies by location


Thus the table would only list those services which should vary based on
where the user is dialing in/connecting.

- Forrest W. Christian ([email protected]) KD7EHZ
iMach, Ltd., P.O. Box 5749, Helena, MT 59604
Solutions for your high-tech problems.                  (406)-442-6648