RGS200-12P loses the ability to...forward DHCP requests? & Scheduled restart possible?

mTS

Hi Guys,

Since 1 or 2 years, we are using multiple RGS200-12P at our location in the production halls. all worked well for the last years, but 1 or 2 month ago i noticed a strange behaviour at 3 (out of ~15) devices.

They lost the ability to forward DHCP requests.

After a reboot of the switch, connected clients get an IP adress almost instantly. but after like...a week or 2, DHCP is no longer working at this switch. 
Clients that are already connected and haveing an IP address, OR if you assign an IP adress manually are working without a problem!

All other clients who try to DHCP (or with ipconfig release/renew) they get stuck at an APIPA.

I've checked the Firmware, but the factory firmware is also the newest (1.00(ABEP.1)C0)

Anyway, i don't even know how to start the troubleshooting. For now, if a client needs a restart or something and the DHCP isn't working i just "manually" restart it via the GUI.

For the meantime...is there a possiblitly to schedule a reboot for these switches? i've googled and found that Zyxel APs have like a scheduled Script Running option where you can perform a restart. is there something similar with switches?

Thanks ahead
mTS

Zyxel_Melen

Hi @mTS,

Welcome to Zyxel community!

According to your description, it looks like the link between switch and DHCP server was down since you say clients get DHCP IP setting after reboot the switch.
When the issue occur again, may you use a client with static IP to ping the DHCP server and the switch?
 
Have you enable DHCP Snooping feature?
If yes, may you share DHCP Snooping table?


In addition, may you provide the system log information and the topology to me to investigate the symptom?



By the way, we don't have a scheduled Script like Zyxel APs to reboot the switch, but you may use SNMP to reboot switch.
The OID .1.3.6.1.4.1.890.1.15.3.2.1 in our common MIB file is use to reboot switch.
The set value of reboot is 1.
You can download the MIB file here.

mTS

Hey @Zyxel_Melen, thanks for the reply, and sorry for my silence since then! Really busy here atm

It happend again today, i've restarted the switch and everything was working again.
While it wasn't able to forward DHCP requests, i was able to ping the DHCP server with 1ms via the "Diagnostics" Menu on the Zyxel WebGui.

Sadly, i didn't had DHCP Snooping enabled, but I enabled it for now and and can provide logs later.

Also sadly, i've forgot to made a Screenshot from the Syslog before the reboot, so i can only show after the reboot:


I'm noticing the Ingress Filter Conflicts - since i'm not a network expert, i've tried to google it but i couldn't get my head around the error. What does that mean? I've seen Ingress Filtering was disabled for almost all ports, i've enabled it now.


For my topology, it looks like this:


As i said, i was able to ping the DHCP Server from the Zyxel Gui while the client wasn't able to get an IP address. After a reboot, everything was working again.

If you can help me out with this i would glady invite you to a beer or coffee

best wishes
mTS 

Zyxel_Melen

Hi @mTS,

Good day.
May you provide the configuration? I would like to check if there has any wrong configuration.

In addition, is the client in same VLAN with DHCP server? Is there any DHCP relay device? May you also add VLAN and port information on the topology?