Opened 7 years ago

Last modified 4 years ago

#8653 new defect

Bridging and Vlans on Segregated Switch

Reported by: Tim Fretz <tim.fretz@…> Owned by: developers
Priority: normal Milestone: Barrier Breaker 14.07
Component: packages Version: Trunk
Keywords: Cc:


I am using an Ubnt LS2 with a recent build of 8.09. The eth0 interface is an IC+ IP175C bridge with 2 physical ports.

PC A/Modem has - connects to eth0 port0 (wan port) - eth0.1
PC B/local PC has - connects to eth0 port4 (lan port) - eth0.2
No PC - connects to ath0 (wireless) - ath0
br0 gets a dhcp address and has eth0.1, eth0.2 and ath0 attached.
br0:1 has

Ping from B to A


  • ssh from B to (openwrt)
  • then start ping from openwrt to PC A

At this point the arp entry in the openwrt box for A is correct and present


  • Follow working setction and then start a ping from B to A

At this point the ping from openwrt box to A stops, the arp table the entry for A is now gone
Stopping the ping from B to A will cause it to start working again and the arp entry to reappear.

More info

Attachments (0)

Change History (4)

comment:1 Changed 7 years ago by anonymous

Problem persists after upgrading to 10.03.

comment:2 Changed 7 years ago by Jérôme Poulin <jeromepoulin@…>

I was looking at ticket #7637, I see problem #7637 has a patch for enabling enable_learning by default on rtl8366rb and such which is a good idea.

However, it seems to break WDS and some ARP stuff, I made a WDS bridge between 2 TL-WR1043ND and if I have the arp entry for the remote router in my ARP table on my laptop, it works, else I see an ARP request going to the remote router, remote answers, it gets in br-lan, out to eth0.1 (from tcpdump side) but does not go out the wire, disabling enable_learning makes the ARP go out correctly, another very weird problem about those switch chips.

comment:3 Changed 6 years ago by epek

The same here.
Some hosts indicate incomplete arp resolution.
It always happens with latest builds when (some) hosts are connected to a vlan-enabled, untagged port of TL-WR1043ND. One host is a ubuntu with 3c509, another is ubuntu with an rtl8169. The same happens, when using an oboard rtl 81xxE nic. Now - to my surprise even a print server is affected by this.

The problem occurs only machines behind those switches and only to a virtualized gateway, all other traffic on the net passed w/o problem. The strange thing is, that it used to work somewhere before build 317xx.

comment:4 Changed 4 years ago by jow

  • Milestone changed from Attitude Adjustment 12.09 to Barrier Breaker 14.07

Milestone Attitude Adjustment 12.09 deleted

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