Debugging a Nagios warning on ssh, I've discovered that gssapi-with-mic is causing long lags in authentication. I've turned it off, but what exactly am I missing? I gather that GSSAPI is a tool for authentication, but what about the -with-mic part?


Message Integrity Code:

The term message integrity code (MIC) is frequently substituted for the term MAC, especially in communications, where the acronym MAC traditionally stands for Media Access Control.

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    MAC doesn't stand for Media Access Control but for Message Authentication Code (see Wikipedia:hmac) – Ikke Jun 19 '12 at 7:09
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    @Ikke Actually it stands for both (which is why MIC has come into use, to disambiguate the two when talking about a MAC (message authentication code) associated with data transmitted across networks that use MACs (Media Access Control addresses)). – voretaq7 Aug 6 '12 at 22:00
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    @voretaq7 You're completely right. I misread the answer. – Ikke Aug 7 '12 at 7:52
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    Oh, I though it was a microphone and I wondered what the heck. – Vlasec Jan 14 '16 at 12:17

The fix is simple: disable attempts to use GSS-API by adding the following to ~/.ssh/config:

GSSAPIAuthentication no

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