Issue with forwarding when creates new interface [was USB Tethering and forwarding]

[Paul Thornton]

Hi,

I can also replicate this behaviour on 10.1-RELEASE by simply creating 
an additional vlan interface.  It affects IPv4 and IPv6 forwarding.

This is taken from a test setup of FreeBSD boxes running Quagga as BGP 
routers - but with a default GENERIC kernel.  This machine has 2x ixgbe, 
4x igb and 2x bce physical interfaces, with a cloned lo1 and vlan0.

[root at test1 ~]# uname -a
FreeBSD test1.prtsystems.ltd.uk 10.1-RELEASE FreeBSD 10.1-RELEASE #0 
r274401: Tue Nov 11 21:02:49 UTC 2014 
root at releng1.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC  amd64


[root at test1 ~]# sysctl -a | grep forwarding
net.inet.ip.forwarding: 1
net.inet.ip.fastforwarding: 1
net.inet6.ip6.forwarding: 1

[root at test1 ~]# ifconfig vlan1 create

[root at test1 ~]# sysctl -a | grep forwarding
net.inet.ip.forwarding: 0
net.inet.ip.fastforwarding: 1
net.inet6.ip6.forwarding: 0


I haven't tried using 10.0 as a router, so don't know if this crept in 
between 10.0 and 10.1 or 9 and 10.

Paul.

On 03/01/2015 13:12, wishmaster wrote:
>
> Hi,
>
> I have been seeing strange behavior of my system lately. After creating new interface the system variable net.inet.ip.forwarding becomes "0".
>
>   E.g. manually load if_ral kernel module, then rel0 interface appears and net.inet.ip.forwarding becomes "0".
>
>   Previously this happened when I attached smartphone with USB tethering is on.
>   May be this is VIMAGE-related... Any ideas?
>
> Below my original first post.
>
>> Hi, list.
>>
>> Server works as router for small network and some services in the jails. When I connect Android-based smartphone and attempt to use USB Tethering, the net.inet.ip.forwarding becomes 0 and I must change it to 1 every time.
>>
>> Is this normal behavior?
>>
>> FreeBSD server.local 10.1-STABLE FreeBSD 10.1-STABLE #1 r275636: Mon Dec 22 11:05:33 EET 2014 wishmaster at server.local:/usr/obj/usr/src/sys/SMS i386
>>
>> Kernel has been compiled with VIMAGE
>>
>>
>> Cheers,
>> Vitaliy
>>