Solved ASUS RT-AC87 System log missing days (Synology issue?)

[Sky]

The System Log in my AC87 is missing all activity between 13 April 12:59:06 and 17 April 09:05:07, a period of about 3-days 8-hrs 6-min 1-sec. There is no space between the log lines, no blanks. You wouldn't even notice it without a close reading of the log. I have my AC87 reboot every day so that makes it a bit easier when scanning. The last thing on the 13th is an LE certificate renewal skip-add '--force' and the next entry is on the 17th for a reboot when the ISP service tech showed up to check out our line speed.
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Apr 13 12:59:01 rc_service: service 8884:notify_rc restart_letsencrypt​

Apr 13 12:59:05 kernel: [Tue Apr 13 12:59:05 DST 2021] Domains not changed.​

Apr 13 12:59:05 kernel: [Tue Apr 13 12:59:05 DST 2021] Skip, Next renewal time is: Mon May 3 23:06:43 UTC 2021​

Apr 13 12:59:05 kernel: [Tue Apr 13 12:59:05 DST 2021] Add '--force' to force to renew.​

Apr 17 09:05:58 rc_service: httpds 262:notify_rc reboot​

Apr 17 09:06:00 iTunes: daemon is stoped​

Apr 17 09:06:00 FTP Server: daemon is stoped​

Apr 17 09:06:00 Samba Server: smb daemon is stoped​

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I have never seen my log display this sort of thing before. Everything before and after is normal routine. I would put up the whole log but, honestly, there is nothing out of the ordinary to see, just this.

During the period I was running some experiments on a new Synology NAS. The NAS logs show normal users' activity over those days. It's as if the logging function—burped—then went on like nothing had happened. Like a cat tripping. Weird.
Sky

23 Apr 2021
ADDENDA
This morning I checked the syslog again. The AC87 properly rebooted per settings the morning of the 18th

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Apr 17 23:08:18 disk_monitor: Got SIGALRM...​

Apr 18 03:15:13 reboot scheduler: [timecheck] The system is going down for reboot​

May 4 22:05:03 syslogd started: BusyBox v1.17.4​

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then again on the 19th but without notating the reboot scheduler

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Apr 18 23:00:37 disk_monitor: Got SIGALRM...​

May 4 22:05:03 syslogd started: BusyBox v1.17.4 <<< Starting boot sequence, no warning like above​

May 4 22:05:03 kernel: klogd started: BusyBox v1.17.4 (2020-07-01 11:37:57 CST)​

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May 4 22:05:28 miniupnpd[503]: shutting down MiniUPnPd​

May 4 22:05:28 ntp: start NTP update <<< End of boot sequence​

Apr 19 03:17:46 miniupnpd[507]: version 1.9 started​

Apr 19 03:17:46 miniupnpd[507]: HTTP listening on port 56252​

Apr 19 03:17:46 miniupnpd[507]: Listening for NAT-PMP/PCP traffic on port 5351​

Apr 19 03:17:46 start_ddns: update WWW.ASUS.COM dyndns, wan_unit 0​

Apr 19 03:17:47 rc_service: ntp 392:notify_rc restart_diskmon​

Apr 19 03:17:47 disk_monitor: Finish​

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then again on the 20th and again failed to notate the reboot scheduler, then went to this, a blank log again:

Apr 20 12:59:06 kernel: [Tue Apr 20 12:59:06 DST 2021] Add '--force' to force to renew.​

Apr 20 23:00:40 disk_monitor: Got SIGALRM...​

Apr 21 12:30:01 rc_service: service 17439:notify_rc restart_letsencrypt​

Apr 21 15:15:53 rc_service: httpds 262:notify_rc start_webs_update​

Notice, no reboot Apr 21, also no log entries at all, which means no reboots either and the current day/time is Apr 23 08:09:55 hrs ... the reboots are missing for the 21st, 22nd, and 23rd, and spotty log entries are here with massive numbers of what should be routine entries absent. ​

The only thing I can think of that has changed with regard to the router is enabling UPnP (yes, I know) to facilitate a function in my Synology NAS. I've disabled UPnP to see if this might be the right track. Any input would be welcome and appreciated.

Sky

 

[Sky]

RESOLVED

Well, I managed to figure this one out.

Sure enough, the Syno has a *known issue* of intermittently messing up the Asus when it writes commands to it to use UPnP. The fix was to return to disabling UPnP and open a port on the router with due security, etc.

Sky