Hello,
I have a setup where two VyOS devices have a MPLS link over GRE.
The tunnel is `tun0`, and the configuration is (relevant part):
```
set interfaces tunnel tun0 address '10.255.0.2/30'
set interfaces tunnel tun0 encapsulation 'gre'
set interfaces tunnel tun0 remote '10.255.255.1'
set interfaces tunnel tun0 source-address '10.255.255.2'
set protocols mpls interface 'dum1'
set protocols mpls interface 'tun0'
set protocols mpls ldp discovery transport-ipv4-address '10.255.1.2'
set protocols mpls ldp interface 'dum1'
set protocols mpls ldp interface 'tun0'
set protocols mpls ldp router-id '10.255.1.2'
```
After the configuration, everything looks good and working fine... Until I do a reboot.
In fact, it seems that after the reboot this sysctl flag is not set:
```
net.mpls.conf.tun0.input = 0
```
If I perform the following actions:
```
delete protocols mpls interface tun0
commit
set protocols mpls interface tun0
commit
```
then the sysctl is restored:
```
net.mpls.conf.tun0.input = 1
```
and everything works again.