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Connection using SSH to a Host Not in DNS/hosts Stalls for Some Time at Connection Initiation (Doc ID 1066024.1)

Last updated on OCTOBER 27, 2023

Applies to:

Linux OS - Version Enterprise Linux 4.0 to Oracle Linux 7.0 with Unbreakable Enterprise Kernel [3.8.13] [Release RHEL4 to OL7]
Oracle VM - Version 2.1 to 3.3.1 [Release OVM21 to OVM33]
Oracle Cloud Infrastructure - Version N/A and later
Generic Linux


ssh, scp or sftp to a node that doesn't appear in DNS or /etc/hosts file is slow to make initial connection.  After the connection is established, the speed is as expected. There are two cases to consider, see below.  Note that in most environments this issue will not occur since IPs will be in /etc/hosts or DNS. 


This is more likely to happen in newly installed test and production environments as DNS or hosts configuration might not be complete yet. Inherently the similar problem may be seen with Oracle VM configurations along with the guest OS installations.


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