Server unexpectedly closed network connection putty to centos


Dear all expert,

I have implemented CentOS server as my Telephony gateway after completed It working fine but a few month after It have issue with SSH. I try to remote to server by putty but it show message ( ver unexpectedly closed network connection)
I can’t remote to server but I can log into server directly by VMware client. I did a server reboot and after reboot it can log in as normal but a next few day It become the same.


try to ping outside network , it seems like there is problem with network connection ,try with ping , if you got result fine there try to ping with your cmd to your vm machine , if you are not able to ping trace your vm for the error , might be issue with selinux .

let me know if you get any issue




It can be caused by at least few possible reasons.

  1. Was your VM IP address changed, did you check it? Run ‘ifconfig eth0’
  2. Did you checked is sshd daemon running? Run ‘service sshd status’ and check for output.
  3. Did you make any changes to sshd config? Run ‘ssh root@localhost’ to check.
  4. Did you change any iptables rules? Is incoming SSH connections allowed now?

Anyway, there are so many possible causes, so I really need more information here.
You can take a look here for few usable links too.


Hi srivastavaashish200,

This server I did’t allow to outside LAN,It could not ping to And about connection, From Client PC can ping to the server and can telnet also.


Hi imort,

  1. VM IP address was not changing.
  2. sshd daemon server is running
  3. I didn’t make any change to sshd config. and when i try to ssh root@lcoahost it shown the resulted ( cannot read from /dev/urandom, No such file or directory).
  4. iptables rules was disable