<p>When printing RFC documents on my A4 format printer I noticed that I print more than it is considered to be one page in RFC document. I figure this is because probably RFC is written in North American paper letter format (216 × 279 mm) and I want to use ISO A4 format (210 × 297 mm). Info on <a href="http://en.wikipedia.org/wiki/Paper_size" rel="noreferrer">Paper size</a>. So my question is if there is some way or program with which I would at least be able to print every letter format page on to the separate A4 format page. I know there will be some unused space at the bottom but at least there will just be one text page per A4 paper page. I tried changing paper size on printer from A4 to letter, but it didn't help.</p>

The RFC documents contain page breaks and such in the form of line printer control codes. Just printing a plain text rfc out of vi / notepad / word / whatever will
probably
not work as expected. Try searching for the rfc in PDF form, they'll be easier to print and the page numbering should be correct. You may be able to find pdfs in A4, else the printer dialogues "shrink to fit" feature should handle it.
Oh and shop around, some PDFs are much nicer than others...
You could find PDF format here
http://tools.ietf.org/pdf/
, for RFC 1928, it's
http://tools.ietf.org/pdf/rfc1928.pdf
.