Re: Yet another X.400 vs SMTP question

Alf Hansen <> Fri, 28 May 1993 14:28 UTC

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From: Alf Hansen <>
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Subject: Re: Yet another X.400 vs SMTP question

Jock et al,

A very good answer from Tony. I could add the following as my personal view:

X.400 has more service elements than SMTP. X.400 can use several underlaying
network protocols (RFC 1006 on top of TCP/IP, TP 0 on top of X.25, etc...)
and is therefore "more open" than SMTP which as far as I know runs on top of 
TCP/IP only.

The big problem with X.400 products is that for some reason, the quality of
the implementations are not mature (yet). There are very few user X.400 user
agents who can compare with the quality of the most popular SMTP agents. This
situation is improving. Right now I am using XEan which can be compared with
XMH. I will soon switch over to ON-Mail which is another excellent X-windows
based user agent. Therer are others.

Another big problem with X.400 systems is that the service management tools
are not mature either.

I would claim that the two big problems above have very little, if anything at
all, to do with the X.400 Standard itself. They have to do with the quality of
the available products.

We could argue forever about X.400 addresses vs. RFC 822 addresses. With PP
and good X.400 user agents, the user can choose which address type she
prefers. Both XEan an ON-mail can handle this. That is why I am using them.

Best regards,
Alf H