I am wondering what is the name of the fonts that are used to write RFCs? For instance, I was reading an RFC and trying to figure out the font name used to write it. Here is a screenshot:

enter image description here

Also, I want to know the corresponding Latex font name as well, such as: courier or \usepackage{courier}.

  • I have no idea whether a font looking like this is available, but have you checked tug.org/FontCatalogue/typewriterfonts.html ? – Skillmon likes topanswers.xyz Jan 16 at 19:07
  • @Skillmon, Yes I did, the last line in my question I mentioned about \usepackage{courier} as well. But I am not sure whether it is the correct one or not. – rakeb.mazharul Jan 16 at 19:09
  • @leonheess I understand, and particularly want to know what font IETF used to publish these RFCs. In Latex, I also wanted to use the same font. – rakeb.mazharul Jan 16 at 19:11
  • @rakeb.mazharul Which browser and which OS are you using? – leonheess Jan 16 at 19:12
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    we could guess but it the font you have specified as the monospace font in your browser so it is easy for you to check. – David Carlisle Jan 16 at 20:24

First of all, RFC is just an abbreviation for "Request for Comment" and does not inherently refer to the IETF.

Secondly, the site you have linked is just displaying the content with the CSS-attribute font-family: monospace. Your browser interprets this and as it is one of the nine generic font familys (serif, sans-serif, cursive, fantasy, monospace, system-ui, emoji, math and fangsong) it will ask the operating system for a fitting font. So it really comes down to how and on which machine you are viewing this.

It could be any of these or a different one altogether:

  • Fira Mono
  • DejaVu Sans Mono
  • Menlo
  • Consolas
  • Liberation Mono
  • Monaco
  • Lucida Console
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  • All good fonts, but none matches the example in the question. The "A" in that example is distinctive, with a small stroke flying off the top to the left, The only typeface I know with that shape is Courier or a clone. Also, all the fonts you list are sans serif, and the example definitely has serifs. – barbara beeton Jan 16 at 19:42
  • @barbarabeeton Agreed -- all examples of Courier (and I seem to have an embarrassing plenty of them plus a quick look at myfonts.com/search/courier) have the distinctive UC 'A' which other typewriter fonts do not. There are dozens of implementations so it is impossible to say with any certainty which this is. Courier it is. – sgmoye Jan 16 at 20:07
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    @sgmoye most likely a clone, because the original Courier is too light for the image. – Skillmon likes topanswers.xyz Jan 16 at 20:08

This seems to be way off topic, but as you say you want to use the font in latex I suppose it almost counts...

The font you see depends on your browser settings. If I view the link you give in firefox on windows it uses the system Courier New font as easily seen by using the right menu inspect element option and looking at the Fonts tab:

enter image description here

Most browsers (certainly Chrome, Edge, internet Explorer) have similar options to see the current settings.

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