ssh connection takes forever to initiate, stuck at "pledge: network"

Connection to one of my servers using ssh takes more than 20 seconds to initiate.

This is not related to LAN or WAN conditions, since connection to itself takes the same (ssh localhost). After connection is finally establised, it is super fast to interract with the server.

Using -vvv shows that the connection is stuck after saying "pledge: network". At this point, authentication (here using key) is already done, as visible here :

... debug1: Authentication succeeded (publickey). Authenticated to ([xx.xx.xx.xx]:22). debug1: channel 0: new [client-session] debug2: channel 0: send open debug1: Requesting [email protected] debug1: Entering interactive session. debug1: pledge: network 

(...stuck here for 15 to 25 seconds...)

debug1: client_input_global_request: rtype [email protected] want_reply 0 debug2: callback start debug2: fd 3 setting TCP_NODELAY debug2: client_session2_setup: id 0 ... 

Server is Ubuntu 16.04. It already happened to me in the past with another server (was Ubuntu 12.04) , nerver found the solution and the problem disapeared after a while...

sshd_config is the default one provided by Ubuntu.

So far I have tried :

  • using -o GSSAPIAuthentication=no in the ssh command
  • using password instead of a key
  • using UsePrivilegeSeparation no instead of yes, in sshd_config


found the answer :

changed UsePAM from yes to no in sshd_config file

After restarting the ssh service, the connection is now immediate to the server. On this server, PAM is linked to ldap, so that is probably the reason, even if here I am connecting with a user declared on the server itself, not an LDAP one.

Well, this is more a way to bypass the issue, not really a solution... I have other servers set up the same way that are not having this issue.

Hope this may help someone...

Category: ssh Time: 2016-07-28 Views: 0
Tags: ssh

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