Yes, I'm bit lazy and use SwOS on that nice home central switch. Earlier fw 2.13 works great about year without any issue but once upgraded to lastest it will hang somehow on 10-20h ..
Every time I will notice that my wifi ap's that are connected to this sw are unavailable and when I log in from my desktop that are directly connected to it it look good. But when login my router (rb4011, with quite basic cfg) I notice that all dhcp leases are gone, only hosts that are with static ip are working.

Once I reboot crs312, everything start working again and all clients get new leases. Tomorrow I need to drop second powerline out and put clockswitch to remain power cable to mitigate issue. But this sound ...

At same time I upgraded ros 7.12.x to 7.14 on rb4011, if it has some bug among this sw.. (yes, my mistake, a) upgrade something that works b) upgrade both on same night)
crs312 is connected to rb4011 with aoc fiber dac (10G).

It seems that I need reboot crs312 now every 24h to keep clients get ip addr with dhcp. Just rebooted sw and all clients are now back in dhcp server lease table.

yup .. again same state... need to reboot crs312 to fix all...

Does anyone know where older versions are available? not found from https://mikrotik.com/download or https://mikrotik.com/download/archive

yup .. again same state... need to reboot crs312 to fix all...

Might be a silly question, but have you tried updating to the latest version?

Nevermind.. It is "Lite" that has 2.18

to keep clients get ip addr with dhcp

Curious.. If you give the hosts static IPs, do they keep working? What is the lease time set to? What happens if you change it?

yup .. again same state... need to reboot crs312 to fix all...

Might be a silly question, but have you tried updating to the latest version?

Nevermind.. It is "Lite" that has 2.18

Question is not silly ... All works nicely on previous version 2.13 and went broken after updated to lastest 2.16.
Tried also reload/reupload lastest second time .. I'm trying figure out is older version available anywhere.. (not found from Mikrotik DL or archive site)

to keep clients get ip addr with dhcp

Curious.. If you give the hosts static IPs, do they keep working? What is the lease time set to? What happens if you change it?

Yes, have now done some debugging .. Hosts that has static ip works ok.
Lease time is "mikrotik standard 10min" ... issue cause always near after 24h uptime .. But, this might be good to test.

I have also CSS326 and in that box latest fw works ok.. but it of course has different switch chip. Also I think that most of CRS312 users may run ROS instead SwOS.

Some cfg:
- DHCP snooping is off
- no ACL
- Mikrotik discovery protocol is on
- snmp enabled
- 5 vlans with port isolation and learning enabled
- some ports has only tagged vlan, some only untagged
- no LAG ports
- all other settings are basically "default" state
- if there is SW behind port of crs312, there is same issue with hosts that are connected to those sw. Most of connected sw are mikrotik, one is zyxel
- my router (rb4011) was connected to crs312 .. first with aoc fiber dac and then tested with rj45 cat6 also .. same issue. Now router is connected to another sw instead this crs312.

sw has now 6d uptime and I set my desktop pc from static to dhcp and it drop nw access as it will not get ip from dhcp server. After change back to static it work as normal.

Added dhcp logging to rb4011 and I don't see any (dhcp) requests from my desktop pc.
It look that after 24h from crs312 reboot, all dhcp traffic are dropped/filtered out until next reboot. With static ip all works ok.

Haaa. Might be resolved now!

in System tab, there is DHCP Snooping and port that provide dhcp service to this area (in my case RB4011 is connected to CSS326 that are connected with dac to CRS312) need to be selected AND next parameter under portlist of snooping ports, "Add Information Option" must be unchecked.

I have tested this now with 2 hosts that are connected to crs312 and current situation look promising.


Let's test it now with this configuration on few days.

Promising update.

Still working ... just added more hosts to crs312 as well another sw and wifi ap ..

Summary of solutions: with SwOS 2.16
- CRS312: in system tab under DHCP Snooping "Add Information Option" need to be unchecked.
- CSS326: in system tab under DHCP Snooping "Add Information Option" need to be checked.
(- RB4011: no changes any configs)

Next step: if all works properly tomorrow, 24h after this update, I will reboot both switches to ensure that all works properly.

near all setups was identical as begining of case, only changes was "Add additional.." checkbox.

Today morning near nothing works. Only hosts that are connect directly crs312 works ok, they got ip addr from dhcp etc ... BUT clients that are behind any connected box between crs312 and host, like wifi box have loss their ip after yesterday..
-> checked that direct connected host get ip after nw cable was small time unconnected
-> moved wifi ap to behind css326, not getting ip from rb4011 that are connected direct to crs312
-> after above finding, I moved rb4011 to css326 and then all wifi clients get ip
-> after router move to css326, then crs312 clients no more get ip

... sad as last night everything works ok.