[ntp:security] [Non-DoD Source] Re: Problems with new ntpd
stenn at nwtime.org
Sat Apr 23 02:37:20 UTC 2016
On 4/22/16 12:43 PM, Prillaman, Jeffrey wrote:
> The bytes themselves aren't always zero, just the leading byte in the
> "Key ID" spot has always been zero. They're not a response packets
> from what I can tell.
OK, well the only things you should be seeing are:
- plain NTP packets
- plain NTP packets with a single MAC field at the end
- - 4 0x00 bytes as the key ID would be a (rare) crypto-NAK
- - 4 nonzero bytes as the key ID would be the key ID:
- - - < 65535 is symmetric key
- - - > 65535 is autokey
- - - followed by:
- - - - 16 more bytes of a 128 bit hash, or
- - - - 20 more bytes of a 160 bit hash, or
- - - - however many bit are needed by the corresponding hash
- plain NTP packets, an autokey EF, and a MAC
Anything else is unexpected.
Harlan Stenn <stenn at nwtime.org>
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