wg-quick up automation fails

[Silvan Nagl]

Hi again,

i just noticed my default interface has MTU 1348 so when i am connected
to this one and use wg-quick it will break. Disconnecting from it first
and than using wg-quick will set higher MTUs on the WireGuard interface
so it wont break for ipv6.

Greetings,

53c70r

On 6/2/19 12:27 PM, Silvan Nagl wrote:
> Hi,
>
> as i already mentioned the problem persists on master branch for me.
>
> Greetings,
>
> 53c70r
>
> On 6/2/19 8:32 AM, XRP wrote:
>> On Sun, 2019-06-02 at 01:49 +0200, Silvan Nagl wrote:
>>> G'day,
>>>
>>> i recently upgrade WireGuard to the latest shipped Debian version
>>> (0.0.20190406-1) and noticed my wg-quick created interface did not
>>> come
>>> up as usual anymore. (Also tried the git master branch) I tried to
>>> single command trough wg-quick's automation to reproduce the error;
>>>
>>> automatic:
>>>
>>> [#] ip link add Y type wireguard
>>> [#] wg setconf Y /dev/fd/63
>>> [#] ip address add X.X.X.X/32 dev Y
>>> [#] ip address add fc00::XXXX/128 dev Y
>>> [#] ip link set mtu XXXX up dev Y
>>> [#] resolvconf -a tun.Y -m 0 -x
>>> [#] wg set Y fwmark 51820
>>> [#] ip -6 route add ::/0 dev Y table 51820
>>> RTNETLINK answers: No such device
>>> [#] resolvconf -d tun.Y
>>> [#] ip link delete dev Y
>>>
>>> manual:
>>>
>>>> ip link add Y type wireguard
>>>> wg setconf Y <(wg-quick strip /etc/wireguard/Y.conf)
>>>> ip address add X.X.X.X/32 dev Y
>>>> ip address add fc00::XXXX/128 dev Y
>>>> ip link set mtu 1268 up dev Y
>>>> resolvconf -a tun.X -m 0 -x
>>>> wg set Y fwmark 51820
>>>> ip -6 route add ::/0 dev Y table 51820
>>> < RTNETLINK answers: No such device
>>>
>>> (MTU may be to low here so i set it higher again)
>>>
>>>> ip link set mtu 1420 up dev Y
>>>> ip -6 route add ::/0 dev Y table 51820 (works now)
>>> breaks up @ this point because of error handling...
>>>
>>> Additionally it could be possible the MTU isn't set correctly.
>> I had a similar problem where I got a "RTNETLINK answers: No such
>> device" error. After that I tried to use the wg-quick version in the
>> master branch and that fixed my problem. I hope that helps.
>>
>> (MTU for IPv6 must be 1280 bytes at least.)
>>
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