问题 在客户端挂载nfs时， 出现

mount.nfs: access denied by server while mounting 192.168.122.199:/mnt/export_dir

解决思路

立即查看服务端日志,journalctl -xe

-- The start-up result is RESULT.May 14 14:07:32 servera kernel: nfsd: recvfrom returned errno 104May 14 14:13:47 servera rpc.mountd[2105]: refused mount request from 192.168.122.1 for /mnt/export_dir (/mnt/export_dir): unmatched host

出现unmatc host， 因为客户端和服务端不在一个网段

[root@servera ~]# exportfs -vaexporting 192.168.122.199:/mnt/export_dir

因为是虚拟机， 所以修改掩码为16

[root@servera ~]# exportfs -vaexporting 192.168.122.199/16:/mnt/export_dir

问题解决