Will adding the "ntp server x.x.x.x" config to a 3560G affect traffic in any way?

[ttrevino1]

I just realized I have 2 switches that don't have any ntp config and need to add this, as the other switches already have. I'd like to add this config during the day, but wasn't 100% sure it wouldn't affect any traffic to the servers already connected to these switches? What will adding this command affect, other than logs? Our 6500 is the ntp master, and I will be pointing these switches to this IP, as the other switches are already.

Thanks, Tony

[Peter Paluch · Accepted solution]

Tony,

You should check your configuration if there are any time-dependent configurations like

• SSL certificates (usually used for HTTPS access on switches) whose expiry may be influenced by the change of time
• routing protocol authentification that uses key chains, with keys being time-limited
• time-based ACLs

If there are not any such configurations then configuring the NTP is completely safe. If there are some time-based configuration parts present, check first if the current time on the switch is similar to the time on the NTP server. If yes then configuring the NTP should not pose any problems because it will merely shift the time slightly. It could be more dangerous to configure NTP while the local time is, say, one year behind.

Best regards,

Peter

[ttrevino1]

Hi Peter, thank you for the response. We don't have anything like you mentioned configured, the switch is 'basically' acting as a passthrough for the servers connected to this switch to talk to the rest of the network, no other time-specific configs at all.

"No downtime" is expexcted here, and I really didn't think this would cause downtime, however, I wanted to confirm my thoughts. Thanks for the help!

[Peter Paluch]

Hi Tony,

You are always welcome.

Best regards,

Peter

[Leo Laohoo]

Adding NTP server details will NOT be disruptive.

I do this all the time.

Change control?  What change control?  You want a CHANGE CONTROL just to add/correct an NTP setting?  *Mushroom cloud over the horizon.*

[siddhartham]

Absolutely not, I do that all the time.

Siddhartha