Re: ANNOUNCE: NCSA X Mosaic 2.6b1 Released

Henrik Frystyk Nielsen (
Thu, 6 Apr 1995 22:33:00 +0500

> > o HTTP header User-Agent now uses a slightly different format, for
> > consistency with other platforms:
> >
> > User-Agent: NCSA Mosaic/2.6b1 (X11; SunOS 4.1.3 sun4m) libwww/2.12 modified
> >
> Is it possible that this field will ever conform to the spec?
> User-Agent: NCSA-X-Mosaic/2.6b1 SunOS/4.1.3 libwww/2.12-modified

Well, it's not far from it. Everything within '(' and ')' is to be considered
a comment which is not part of the field, but is allowed. So what is left is
the two phrases:

NCSA Mosaic/2.6b1 and libwww/2.12 modified

Here the problem is that both contain a space which is not allowed in a token.

A User-Agent field like

User-Agent: NCSA-Mosaic/2.6b1 (X11; SunOS 4.1.3 sun4m) libwww/2.12-modified

would be OK.

-- cheers --

Henrik Frystyk
+ 1 617 258 8143
World-Wide Web Project,
MIT/LCS, 545 Technology Square
Cambridge MA 02154