sss_ssh_knownhostsproxy prevents connection to machine without reverse address

Issue

We have a setup where IDM clients are connecting to a host via SSH, and where it's difficult for us to set the reverse DNS entry for the host's IP address.

On the client, we use the "--configure-ssh" option when we run ipa-client-install. When we try to establish an SSH connection, it fails with the following messages:

OpenSSH_5.3p1, OpenSSL 1.0.0-fips 29 Mar 2010
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Executing proxy command: exec /usr/bin/sss_ssh_knownhostsproxy -p 22 server2.example.com
debug1: permanently_drop_suid: 1003400015
debug1: identity file /home/jump-sc1/.ssh/identity type -1
debug1: identity file /home/jump-sc1/.ssh/id_rsa type 1
debug1: identity file /home/jump-sc1/.ssh/id_dsa type -1
Reverse lookup failed
ssh_exchange_identification: Connection closed by remote host

When we run the sss_ssh_knownhostsproxy command, it shows the same "Reverse lookup failed" error.When we remove the ProxyCommand option from /etc/ssh/ssh_config, the connection works