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sshd

"UseDNS no" is conflict with "Match User xxx"?

Last night I added UseDNS no to my sshd_config, after I restarted ssh via sudo service ssh restart, I found sshd not started and there is no process listened on port 22, but after I deleted UseDNS no, it will work as before.

I have compared with another server's sshd_config, only three lines are different (this server used sftp, so these lines are added): 

Match User editor
ChrootDirectory /opt/ljmall-staging/var/editor-rootfs
ForceCommand internal-sftp

I have tried commet ChrootDirectory and ForceCommand, it doesn't work, it means Match User and UseDNS no is conflicted?

Server OS: Ubuntu 14.04.3 LTS
Openssh-server: 1:6.6p1-2ubuntu2.7
Solution

  • They are not in conflict, but Match creates a new conditional block and UseDNS is not allowed in the conditional blocks.

    Moving UseDNS above the Match block will solve your issue.