Traficc thank you very much for your answer,but the problem is not solved.
i moved ipp.txt file in ccd folder.
And than i edited ifconfig-pool-persist /etc/openvpn/ccd/ipp.txt
root@xxxxr:/etc/openvpn/ccd# ls -l
-rw-r--r-- 1 root root 67 Mar 25 13:40 client1
-rwxrwxr-x 1 root root 0 Mar 26 16:45 ipp.txt
i added client1,10.2.1.9 in ipp.txt file.
i restarted openvpn server.But the file was again empty. 🙁
When i restarted to my open vpn server,my openvpn server log is
Sat Mar 26 16:47:50 2016 /sbin/ip addr add dev tun0 local 10.2.1.1 peer 10.2.1.2
Sat Mar 26 16:47:50 2016 /sbin/ip route add 10.2.1.0/24 via 10.2.1.2
Sat Mar 26 16:47:50 2016 Listening for incoming TCP connection on [undef]
Sat Mar 26 16:47:50 2016 TCPv4_SERVER link local (bound): [undef]
Sat Mar 26 16:47:50 2016 TCPv4_SERVER link remote: [undef]
Sat Mar 26 16:47:50 2016 MULTI: multi_init called, r=256 v=256
Sat Mar 26 16:47:50 2016 IFCONFIG POOL: base=10.2.1.4 size=62, ipv6=0
Sat Mar 26 16:47:50 2016 IFCONFIG POOL LIST
Sat Mar 26 16:47:50 2016 MULTI: TCP INIT maxclients=100 maxevents=104
Sat Mar 26 16:47:50 2016 Initialization Sequence Completed
When i restarted to my openvpn server,My vpnclient1 is connectionnormally lost.Client log is ;
root@yyyyy:/etc/openvpn# Sat Mar 26 16:42:25 2016 Connection reset, restarting [0]
Sat Mar 26 16:42:25 2016 /sbin/ip route del 10.2.1.0/24
Sat Mar 26 16:42:25 2016 /sbin/ip route del 192.168.55.0/24
Sat Mar 26 16:42:25 2016 /sbin/ip route del 192.168.3.0/24
Sat Mar 26 16:42:25 2016 Closing TUN/TAP interface
Sat Mar 26 16:42:25 2016 /sbin/ip addr del dev tun0 local 10.2.1.9 peer 10.2.1.10
Sat Mar 26 16:42:25 2016 SIGUSR1[soft,connection-reset] received, process restarting
Sat Mar 26 16:42:25 2016 Restart pause, 5 second(s)
But then,client cannot again connection.
Can you help me ? regards