Symmetricom Time Server Manual Do Utilizador

Chapter 4: Serial or Telnet I/O Functions

The NTP client “ntp.keys”

 

file is identical to the one on the NTP server.  For the specific 

keys used by the NTP server, the NTP client must have the identical line in its version of 
the file.  You’ll want to use your own hard-to-guess key names, using random letters.  The 
critical lines of the “ntp.keys” file are:

Id    M    Value
----  ---  --------
1     M   Symmetricom
2     M   xyz123

where 1 and 2 are key identifiers.  

The first column is the key identification number, which may range in whole positive 
numbers from 1 to 65,535.  The second column is the type of key, which is always set to 
the letter M when using MD5 authentication.  The third column is the private key that is 
ASCII text from 1 to 32 characters in length.

For NTP client authentication, the line 

trustedkey 1 2

 in the “ntp.conf” file is required 

to enable the private keys 1 and 2 from the “ntp.keys” file.  The line 

bclient

 is required 

for broadcast time packets to be processed by the NTP client.  In this case, sample 
information from a client “ntp.conf” file might look like:

trustedkey 1

 

2

bclient

Sample information in a client “ntp.keys” file might look like:

1

M

Symmetricom

2

M

longshot

When you invoke the NTP client at the command line, use the following options:

•

–b

 

to turn on broadcast reception

•

–k /etc/ntp.keys

 

to specify the name and location of the keys file

•

–d 

for debugging.  

An example command line might look like:

After configuring all MD5 keys, carry out step 4 in the configuration procedure outlined 
above.