09-21-2021 08:18 AM
Hello,
I have a cisco 881 router which loses its time every time i restart it. To configure its time, I use the command "clock set hh: mm: ss 21 sept 2021" and I save its configuration. But once the router has restarted, the time displayed is February 06, 2036, so the dhcp service is not functional but the rest of the configuration is OK.
09-21-2021 08:40 AM - edited 09-21-2021 08:56 AM
As far as I remember there is no mechanism that saves time in case of restart.
You need to configure SNTP/NTP to synchronize the time.
09-21-2021 08:53 AM
Hello,
it used to be that the lower end routers did not have an internal battery for the clock, I think the 800 series routers still don't, that is why the time you set is lost when you reboot.
Configure NTP or SNTP:
ntp server time.google.com
sntp server 1.pfsense.pool.ntp.org
09-21-2021 09:48 AM
Hello,
Based on https://www.cisco.com/c/en/us/td/docs/routers/access/800/hardware/installation/guide/800HIG.pdf , Page 1-147, the 880 series have a battery but unfortunately, it is non-replaceable. It is very likely indeed that in the original poster's router, it has died.
I just find it weird that after the reload, the date is in the future, not in the past as it used to be with older routers.
Best regards,
Peter
09-21-2021 03:33 PM
Cisco routers do not keep time. Even if the time is manually configured, the on-board clock will still drift.
Cheap NTP server (stratum 1) can be made by using Raspberry Pi.
10-08-2021 08:22 AM
"Even if the time is manually configured, the on-board clock will still drift."
Yea, system devices that keep poor time have always, somewhat, amazed me because I've always wondered why they cannot, if powered by public AC, "count" that (which tends to be very, very precise - how often does your cheap AC clock need time adjustment). Of course, as you (and others) also noted, there's NTP.
In any case, some Cisco devices, with an on-board clock and can also occasionally (if configured) also sync their on-board clock with NTP. Then if you lose NTP access, or during the initial boot (before system reacquires NTP sync), timestamps will often be fairly close to correct time.
10-08-2021 05:44 AM
ntp master
ntp update-calendar
ntp server 132.163.97.3
THIS WILL AUTO UPDATE THE TIME
10-08-2021 05:59 AM
@SAMEHELSAMMAK wrote:
ntp master
Never, ever, use this command.
This is an archaic command that is no longer relevant in present times.
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