Synology RS815RP+ Keeps going offline

Hi all,
I’ve got a new Rackstation RS815RP+ which I added LibreNMS to monitor which it started logging statistics all fine and happy, however periodically NMS will warn that the unit has lost connection/gone offline but then come back again, then keep repeating this process.

Normally NMS is pretty on the ball if something actually does go offline but from what I can see the Rackstation has been operating normally, I’m not really sure what else I comment on the unit itself besides using two LAN connections in bonded mode for fault tolerance and also has using power supplies.


Check the logs on the Synology box, seen issues before of ‘ddos’ protection blocking snmp. Also please ensure you’re install is fully up to date.

Can’t see anything in particular in it’s logs and DDOS protection was already turned off, I’ll leave it running for for awhile to see if anything gets logged.

NMS is on version 699e99e - Wed Apr 05 2017 22:48:05 GMT+0100
Synology is running DSM 6.1-15047 Update 2 2017/03/21

what happens if you run ping -t for a day or so ?
does it show time outs at the same time that nsm is reporting it being ofline.

When it’s down the webui will tell you whether it’s snmp or icmp ( eventlog has this info) - which is it?

By the looks of it ICMP, and looking more closely it’s likely the unit itself as it wont respond to pings even though the web interface etc still works fine.

NMS says its online now so I’m going to run a ping log until it drops out to see if anything tallys up, to see if it makes any difference I’ve enabled the built in Firewall and allowed ICMP through to our subnet to see what happens.

check if powersaver is not doing anything funky with services or so

Pretty sure I’ve found the culprit… good 'ol DNS. Although I’m running the unit on a bonded LAN when I first set it up with two LAN connections it acquired two IP addresses, so I believe rather than doing a round robin pinging the Synology hostname would just fail.

After cleaning up DNS and rebooting NMS it seems to be logging the unit fine with no dropouts.