[26641] in North American Network Operators' Group
Re: Selection of Appropriate Local SMTP Relay
daemon@ATHENA.MIT.EDU (Forrest W. Christian)
Tue Jan 11 00:45:51 2000
Date: Mon, 10 Jan 2000 22:42:04 -0700 (MST)
From: "Forrest W. Christian" <forrestc@iMach.com>
To: Daniel Senie <dts@senie.com>
Cc: Joe Abley <jabley@patho.gen.nz>, nanog@merit.edu
In-Reply-To: <387A7AFF.1D953E83@senie.com>
Message-ID: <Pine.BSF.3.96.1000110222525.438A-100000@workhorse.iMach.com>
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Errors-To: owner-nanog-outgoing@merit.edu
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:
223.255.255.1 - Primary DNS
223.255.255.2 - Secondary DNS
223.255.255.3 - SMTP Mail
223.255.255.4 - Time Server
You could very easily support this in ANY network. No additional
HW/software required.
Specifically:
config> ip route 223.255.255.1 255.255.255.255 dns.ser.ver.addr
config> ip route 223.255.255.3 255.255.255.255 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
etc....
Thus the table would only list those services which should vary based on
where the user is dialing in/connecting.
- Forrest W. Christian (forrestc@imach.com) KD7EHZ
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