TrueTime IRIG NTS-100, Руководство пользователя

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1/20/97
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using the key ID specified by the client request. If a packet does not send the correct
authentication signature, it is silently dropped.
6.2.2 A TrueTime NTS can contain up to 16 MD5 authentication keys. MD5 keys are entered
and maintained through the standard TrueTime keypad and serial interfaces. Therefore,
for security reasons, the TrueTime time server must be physically isolated from
unauthorized users. MD5 keys must be changed on a regular schedule as a further
security measure. Persons privileged to carry and maintain keys must have appropriate
clearances and be trained for handling secure information. Note: Keys that are no
longer trusted (are potentially compromised) must be deleted from the TrueTime MD5
key table.
6.3 KEYPAD MD5 CONFIGURATION
6.3.1 To configure NTP MD5 from the keypad, press the status function button first and then
press FUNC/ENTR 36. This takes you to the network configuration menu. Continue
pressing the up-arrow key until the
Display/Set NTP MD5 Auth prompt is displayed.
Press FUNC/ENTR to start configuration for NTP MD5. This takes you to the menu titled
MD5 Main Menu: . There are three menu choices from this menu: 1) Modify MD5 keys ,
2) Output On/off, and 3) Back one menu . Note for all TrueTime menus: the up and
down arrow keys scroll through the list of menu items and FUNC/ENTR actuates the
selected menu option.
6.3.2 Pressing FUNC/ENTR for the Modify MD5 keys option takes you to the menu where you
may edit MD5 keys (or view them). Output On/off specifies a menu where you can
enable NTP MD5 authentication for NTP packets broadcast by the TrueTime time server.
Note: At this time, NTP broadcast is not yet available and this menu serves no useful
purpose until that time. The
Back one menu choice returns to the previous menu.
6.3.3 Pressing the Modify MD5 keys menu takes you to the MD5 Edit Menu :. In this menu you
may choose: 1) Edit a Key , 2) Add a Key , 3) Delete a Key , 4) Delete all Keys , or 5) Back
one menu . If you press Edit a Key , then you will be able to scroll through the list of all
currently entered MD5 keys and up to sixteen key identifiers can be stored in sorted
numerical order, plus a
Back one menu entry that will take you to the Modify MD5 keys
menu. Pressing FUNC/ENTR on a particular key identifier takes you to the prompt
ENTER MD5 key up to 31 ASCII char . Pressing FUNC/ENTR again displays the current
value of the MD5 key. You may use the up and down arrows to select the character
value at a position in the MD5 string and the left and right arrows move to other character
positions. Note: It is easier to edit the MD5 keys using the serial command. Pressing
FUNC/ENTR accepts any changes and takes you to the
Save key edit? prompt. Next,
use the up and down arrows to select Yes or No and FUNC/ENTR to activate the
command. Note: you can use the edit function to just view MD5 keys and select No
when asked to save the key changes. Pressing Yes or No takes you back to the MD5
Edit a Key: menu and pressing Back one menu takes you back to the MD5 Edit Menu:.
6.3.4 In the MD5 Edit Menu:, selecting Add a key takes you to the menu where you may add a
new MD5 key. Your first prompt is Enter Key ID: followed by the default value of
0000000001. You may edit the key ID in the range from 1 to 4294967295. Press
FUNC/ENTR and when you finish with the key ID, you will see the
MD5 key up to 31
ASCII char prompt. Press FUNC/ENTR again and you can enter the actual MD5 key as
you would in the edit menu. Press FUNC/ENTR when done and you are taken to the
prompt
Add this key?. Select Yes or No in the same way you did for the edit menu and
you can return to the MD5 Edit Menu: by pressing the Back one menu option. Note: