lance@lance-AcerOne:~$ sysctl -a | grep ip_forward
sysctl: permission denied on key 'fs.protected_hardlinks'
sysctl: permission denied on key 'fs.protected_symlinks'
sysctl: permission denied on key 'kernel.cad_pid'
sysctl: permission denied on key 'kernel.usermodehelper.bset'
sysctl: permission denied on key 'kernel.usermodehelper.inheritable'
net.ipv4.ip_forward = 1
sysctl: permission denied on key 'net.ipv4.tcp_fastopen_key'
lance@lance-AcerOne:~$ sudo sysctl -a | grep ip_forward
net.ipv4.ip_forward = 1
lance@lance-AcerOne:~$