arp request not working in a Layer2 Bridge Connection on Ubu

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mstenz
Posts: 42
Joined: Wed Mar 19, 2014 9:36 pm

arp request not working in a Layer2 Bridge Connection on Ubu

Post by mstenz » Mon May 22, 2017 5:34 pm

Hi,

i have a setup of VPN Server on Windows and a VPN Bridge on Ubuntu. I use this scenario also for other bridge connections that work fine, now this bridge is installed on a provider that runs openstack platform on kvm i have not used before (Prom mode is enabled).
the problem i have is that the Softether Tunnel seems to be up, i see the local ip of the bridge and also see the virtual IP from my L3 switch. but it seems there is no arp resolution possible trough the tunnel.

this is the example output from the bridge:
root@sevpngw:~# ip neigh
10.xx.12.251 dev eth0 FAILED
10.xx.12.1 dev eth0 lladdr fa:xx:xx:6c:da:17 REACHABLE

We have already checked a lot and i don't know where can be the issue. Any idea?

thisjun
Posts: 2363
Joined: Mon Feb 24, 2014 11:03 am

Re: arp request not working in a Layer2 Bridge Connection on

Post by thisjun » Wed May 31, 2017 5:22 am

There is limitation of localbridge on Linux.
http://www.softether.org/4-docs/1-manua ... r_Mac_OS_X

mstenz
Posts: 42
Joined: Wed Mar 19, 2014 9:36 pm

Re: arp request not working in a Layer2 Bridge Connection on

Post by mstenz » Wed May 31, 2017 9:43 am

thx. none of this limitations apply to us as this is running on either CentOS or Ubuntu (same issues on both OS). We have fullly root access to the machines

thisjun
Posts: 2363
Joined: Mon Feb 24, 2014 11:03 am

Re: arp request not working in a Layer2 Bridge Connection on

Post by thisjun » Thu Jun 15, 2017 4:52 am

>Limitations within the Linux or UNIX operating system prevent communication with IP addresses assigned to the network adapter locally bridged from the VPN side (Virtual Hub side).

mstenz
Posts: 42
Joined: Wed Mar 19, 2014 9:36 pm

Re: arp request not working in a Layer2 Bridge Connection on

Post by mstenz » Thu Jun 15, 2017 8:52 am

thx. i know this limitation. But this is not the problem here.
The IP address of the L3-Switch is for example not pingable from the subnet where the Bridge runs.
The tunnel is up. Also a network expert had a look and don't found the issue that arp is incomplete.

thisjun
Posts: 2363
Joined: Mon Feb 24, 2014 11:03 am

Re: arp request not working in a Layer2 Bridge Connection on

Post by thisjun » Thu Jun 29, 2017 7:49 am

It seems promiscuous mode doesn't work.
Could you re-check it?

Is the IP address of virtual L3 switch valid?

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