No more sessions available' / channels not closing issue

Jakub Jelen jjelen at
Tue Sep 12 17:57:52 AEST 2017

On Mon, 2017-09-11 at 10:30 +0000, Mickel Daelmans | Add to Favorites
> Hi all,
> We've run into a curious issue.
> We run CentOS 6.5 with openssh installed (OpenSSH_5.3p1, OpenSSL
> 1.0.1e-fips 11 Feb 2013 by default). We connect to this server
> through sftp (Subsystem sftp internal-sftp) using the java JSch
> library. When opening many sftp channels on a single ssh session
> OpenSsh does not seem to release the sftp channels closed from the
> client side when there are still sftp channels open that are opened
> later than the channel that is closed..  Eventually resulting in "No
> more sessions available".

The obvious questions: Can you reproduce it with OpenSSH client or only
with the java library? Can you reproduce it with the latest OpenSSH
server? In this old OpenSSH version, it can be cause by many factors.

Jakub Jelen
Software Engineer
Security Technologies
Red Hat, Inc.

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