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We are using cisco catalyst 3750x 24 port switch series

How to Change the Exact Date(Singapore) on a Switch

ASW-G-L09-001#show running-config
Building configuration...

Current configuration : 11883 bytes
!
! Last configuration change at 15:46:32 PST Wed May 18 2011 
!
version 15.2
no service pad
service timestamps debug datetime msec localtime
service timestamps log datetime msec localtime
service password-encryption
service sequence-numbers

aaa new-model
!
!
aaa authentication login default local
!
aaa session-id common
clock timezone PST 8 0
switch 1 provision ws-c3750x-24p
system mtu routing 1500
ip routing
!
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  • If any of the answers here answered your question, please mark it as the accepted answer so this question doesn't continue to show up as unresolved. Alternatively, you can post your own answer and mark that.
    – Jesse P.
    Dec 4 '20 at 2:42
7

The order of operations is important because setting the time first will result in the time being incorrect after issuing the zone commands, so what you need to do is:

First, you set the regular time zone at the configure terminal prompt using:

clock set timezone <standard zone> <offset>

For example: clock set timezone EST -5

Then, you set the daylight-savings-time zone from a configure terminal prompt using:

clock summer-time <daylight-savings-zone> recurring

For example: clock summer-time EDT recurring

(if your country doesn't use daylight-savings-time you can remove it by using no clock summer-time)

Finally, you set the time and date from the privileged exec prompt, using:

clock set <hh:mm:ss> <Month> (in abbreviated format) <Day> <Year>

For example: clock set 10:05:45 Oct 07 2020

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    Great answer. Maybe it would be worth adding information on how to configure NTP.
    – JFL
    Dec 3 '20 at 13:51
  • @JFL Thanks. Maybe, but I didn't want to get into all of that, though, and then have to get into NTP authentication, which stratums to use, source interfaces, etc.
    – Jesse P.
    Dec 3 '20 at 14:05
4

To set the clock to Singapore time, first set the timezone. Enter this command in config mode:

router(config)# clock timezone SGT 8

Then you can either set the clock manually (as @jessep shows) or use network time protocol (NTP) to get the correct time from a reliable source. If your router has Internet access, you can use a public ntp server. For reliability, you can configure more than one source. Here's an example using two sources from sg.pool.ntp.org:

router(config)# ntp server 51.79.156.52
router(config)# ntp server 210.23.25.77

To check the time, type

show clock

To verify that your router is synced with the time source, type

show ntp status
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    I cannot recommend using a random selection of IPs for any pool member. Pool membership can (and does) change all the time. The address you use could drop from the pool at any time, without warning. If you want to use a pool server, your NTP software must be able to use hostnames (and preferably support pool types by periodically rechecking the name.) Cisco IOS NTP does not do either of these. The hostname will be resolved on entry and the address recorded in the configuration. If you're going to use NTP, know your servers.
    – Ricky
    Dec 3 '20 at 17:51
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    @Ricky I understand your point, but as you say, IOS doesn't do dynamic lookups. So either you periodically check your servers, or you stand up your own reference source. For most network uses like logging, it's more important to have a common clock than an accurate one. For a small network, your solution is impractical.
    – Ron Trunk
    Dec 3 '20 at 18:36
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    I'm saying pick a time source that's known to you, not something out of pool.ntp.org. There are lists of local servers that may be available to the OP. Some ISPs make their clocks available to customers. I use several that have user mail lists to alert of any maintenance or changes. It's also possible to setup your own server to act as a local time server -- with software that supports pool correctly. Even something as small / cheap as a RPi can do this. (I use a surplus UCS EHWIC in my router.)
    – Ricky
    Dec 3 '20 at 18:51
  • @Ricky Even though you're technically not supposed to, I like to use Tick and Tock (192.5.41.40 and 192.5.41.41) since I know they're static and always work.
    – Jesse P.
    Dec 3 '20 at 19:05
  • I must point out that giving example of only using 2 NTP servers is problematic. General convention is that you use 4-5 NTP sources to provide minimal protection against falsetickers and/or sources that go down. Minimum you should have is 3. A point to ntp.org page for selecting offsite servers would also not go amiss.
    – YLearn
    Dec 3 '20 at 21:34

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