Could not open outbound connection?

Last modified on 9 Mar, 2021. Revision 4
"Could not open outbound connection?" message when using the Ping CLI command
Up to date for
cOS Core 12.00.xx
Supported since
cOS Core 8.x
Status OK
Peter Nilsson


When i perform a ping from the CLI console i get the following message : “Could not open outbound connection?” What is the reason for this?


There are many of reasons for this, below is a list of both common and uncommon reasons.

  • Failed to find a route to the destination IP
  • Failed to find a route to the source IP
  • The connection table is full (and conn-replace fails)
  • Failed to acquire a new ICMP ID or source TCP/UDP port for NAT'ing
  • UDP Src Port 0 is specified, but not allowed (by setting)
  • Failed to acquire an IP from the NAT pool
  • SLB fails to apply the configured policy
  • Threshold rules does not allow a new connection at this stage

The first two, “Failed to find a route to dest/src IP” is the most common causes of this message.

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