RFC 786

MAIL TRANSFER PROTOCOL: ISI TOPS20 MTP-NIMAIL INTERFACE 💌

Title block: this is RFC 786 🎀, from the Network Working Group. The authors are S. Sluizer and J. Postel (ISI), and the date is July 1981 🗓️. The header doesn't list a category, and it doesn't say this one obsoletes or updates anything. 💅

INTRODUCTION ✨

Okay bestie, so this doc defines the ISI TOPS20 interface between the Mail Transfer Protocol (MTP) and the Network Independent Mail Protocol (NIMAIL) 🦋. It does this by describing the files that make the interface work. Each file's internal structure and name are explained below. 🧚

To really get MTP and all its terms, you need RFC 780 "Mail Transfer Protocol", RFC 784 "ISI TOPS20 Implementation", and RFC 785 "ISI TOPS20 File Defintitions" 📚. NIMAIL itself is written up in IEN 169, "A Simple NIFTP-Based Mail System". 🌸

DESCRIPTION 💜

1. NIMAIL to MTP

NIMAIL hands mail over to MTP using the files specified in RFC 785 📨.

2. MTP to NIMAIL

Now for the other direction 👀. MTP hands mail to NIMAIL in files that look like this:

address <CR><LF>
address <CR><LF>
address <CR><LF>
<CR><LF>
Via: USC-ISIE; date-time <CR><LF>
header
 .
 .
 .
<CR><LF>
body
 .
 .
 .

Each address has this shape 🫶:

user%host%host%host@host

Every address in the same file has the same @host part 💖.

The date-time uses the default TOPS20 ODTIM format, which is dd-mmm-yy hh:mm:ss (24 hour time) ⏰.

The files are named arbitrary.NIMAIL.-1 🗂️. The arbitrary part is basically a date-time encoding so humans can read it. NIMAIL does not care at all what that part says 🙈. The files go into the NIMAIL directory on ISIE 📁.

DISCUSSION 🔥

Both NIMAIL and MTP transform the address information so the other system gets the input it needs. It's giving teamwork 👯.

NIMAIL to MTP

Say mail shows up at NIMAIL with this information:

joe%hostx%hosty%hostz@isie

MTP then receives it as:

FROM: <NIMAIL@ISIE>
TO: <@hostz,@hosty,joe@hostx>

MTP to NIMAIL

Now say mail shows up at MTP like this:

FROM: <sam@SRI-NIC>
TO: <@ISIE,@hostz,@hosty,joe@hostx>

NIMAIL gets it as:

joe%hostx%hosty@hostz

Via: ISIE

And that's the whole interface, no cap! 🌈💅👑