OpenWrt Forum Archive

Topic: Issue relayd Bridge(Wifi to Ethernet) Ip problem

The content of this topic has been archived on 12 Apr 2018. There are no obvious gaps in this topic, but there may still be some posts missing at the end.

Hello,

i got an issue by using the relayd function of OpenWrt. I use an raspberry pi b+ with OpenWrt( DD-r48151) as WLAN to LAN bridge via relayd.
Everything works fine i can connect from my computer connected with the Wifi to a device connected to the LAN interface of the pi. I also managed to establish a connection from the device directly to the pi to trigger some events on the bridge.
So my device has two ip´s. One for the connection to the wireless lan which is bridged and one ip for the lan connection between device and bridge. Also this works fine.
I run such a system in my company with many of those bridges(which all got a fix ip on the network) and i got a high utilization of the wifi network and some other problems.
So i used wireshark to check it and i found the problem really fast. First of all there were a high amount of ARP packages on wifi side and i saw that there were also a high amount of gratuitous arps containing ip adresses from the lan network (between bridge and device).
That causes serveral problems. I gave every device a static wifi ip but the same lan ip( because i don´t need this ip in my network and use it just for the communication with the bridge). So all bridges sending gratuitous arps with the same lan ip into my network which causes much unnecessary Arp traffic(causes in high Network utilization) and address conflicts.
I read the wiki from relayed before configuring the bridges and it says that the ip´s configured on the Lan side are just pseudo ip´s and they wont be accessible from the other network.

Well my problem is, that the ip´s used for communication with the bridge are told into the wireless network so i can reach those ip´s from outside.
So i need to stop the bridge sending those informations into the wifi network and only allow the traffic for the wireless ip´s.

I hope i explained it good enough and it´s not too confusing.
If someone have an idea how to solve this feel free to post it. Thanks

greetings

Patrick

I checked again the relayed page of OpenWrt
https://wiki.openwrt.org/doc/recipes/relayclient
and one of the sentences below the first picture says

It is important to notice that the 192.168.2.0 network in the above picture is not going to be used by any clients, but relayd requires the lan interface be in a different subnet to work.

So why my Clients sending out gratuitous Arps for the 192.168.2.0 network i configured...
Also i can reach those ip´s from my devices which are configured with two ip adresses.
Is this a known bug or did i missunderstand something

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