@Yongzhi Pan: Let's get to the bottom of this. Please install resolvconf, reboot, connect to VPN, check that /etc/resolv.conf is wrong. Then send the output of
ls -l /etc/resolv.conf
cat /etc/resolv.conf
ls -l /run/resolvconf
ls -l /run/resolvconf/interface
for F in /run/resolvconf/interface/* ; do echo === $F === ; cat $F ; done
ls -l /etc/resolvconf/resolv.conf.d
for F in /etc/resolvconf/resolv.conf.d/* ; do echo === $F === ; cat $F ; done
and also say what you think the contents of /etc/resolv.conf should be.
@Yongzhi Pan: Let's get to the bottom of this. Please install resolvconf, reboot, connect to VPN, check that /etc/resolv.conf is wrong. Then send the output of
ls -l /etc/resolv.conf /interface /interface/ * ; do echo === $F === ; cat $F ; done /resolv. conf.d /resolv. conf.d/ * ; do echo === $F === ; cat $F ; done
cat /etc/resolv.conf
ls -l /run/resolvconf
ls -l /run/resolvconf
for F in /run/resolvconf
ls -l /etc/resolvconf
for F in /etc/resolvconf
and also say what you think the contents of /etc/resolv.conf should be.