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Phillor
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Joined: Sat Apr 08, 2023 4:16 pm

DHCP not working when Interface of a bridge goes down

Sat Apr 08, 2023 4:35 pm

Hi there,

I'm a bit desperate after hours of troubleshooting I hope that I find help here.
I have a RB4011iGS+ with routerOS 7.8 installed. The problem I'm going to describe was not present before the update to 7.8 although the 7 branch was installed prior to the update I just don't know which minor version it was anymore.

So I have one bridge present on my device. There are 4 VLANs created on top of this bridge. Every VLAN has an IP address and a DHCP Server configured. Ether2 and Ether10 are assigned to the bridge. VLAN filtering on the bridge is active. VLAN101 (Client LAN) is untagged on ether2 via the bridge. Everything is working fine here. My computer gets an ip address via DHCP and I can surf the internet.

VLAN102 (MGMT LAN) is untagged on ether10 via bridge + VLAN100 (Client Wifi) is tagged on ether10 via bridge. On ether10 there is a AP plugged in getting power via PoE. So the AP itself gets an ip address in the VLAN102 via the configured DHCP server on the mikrotik. All the Wifi clients packets/frames are getting tagged with VLAN 100 by the AP and are getting an ip address in this VLAN via the configured DHCP on the mikrotik. So far so good, everything is working.

As soon as I unplug my computer from ether2 or shutting it down, causing ether2 on the mikrotik to go down, all my Wifi Clients in VLAN100 don't have a network connection anymore. They are still connected to the SSID but I can not reach any IP address anymore and they are seemingly not able to request a new DHCP address.

So I was trying to troubleshoot this problem for quite a while now and was not able to find the cause of this problem so today I decided to give the RB4011 a factory reset and start from scratch. Guess what? Same problem.

Maybe you guys can help me out with this and already know by now can assume what my problem ist because I'm not very experienced with routerOS. If you need any more information like the configuration please let me know.

Thank your very much in advance!
 
MarcSN
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Joined: Wed Jul 01, 2020 7:18 pm

Re: DHCP not working when Interface of a bridge goes down

Sun Jun 04, 2023 9:34 pm

Got the exact same problem on a Routerboard 1100AHx4. Afaik thats the same Hardware as the RB4011 (minus the sfp+ port).
Edit: I noticed this Issue on 7.9. Upgrading to 7.9.3 did not help. Downgrading to 7.7 seems to fix it.
Edit2: seems to be fixed in 7.10rc3
Last edited by MarcSN on Sun Jun 04, 2023 11:44 pm, edited 1 time in total.
 
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anav
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Re: DHCP not working when Interface of a bridge goes down

Sun Jun 04, 2023 9:51 pm

YOu might want to try 7.892 stable firmware to see if the problem persists./

Also you could post your config for revew ( minus router serial # and any public WANIP information.

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