Editing Internet Key Exchange (section)

===Problems with IKE===
Originally, IKE had numerous configuration options but lacked a general facility for automatic negotiation of a well-known default case that is universally implemented. Consequently, both sides of an IKE had to exactly agree on the type of security association they wanted to create{{snd}} option by option{{snd}} or a connection could not be established. Further complications arose from the fact that in many implementations the debug output was difficult to interpret, if there was any facility to produce diagnostic output at all.

The IKE specifications were open to a significant degree of interpretation, bordering on design faults ([[Dead Peer Detection]] being a case in point{{Citation needed|date=June 2015}}), giving rise to different IKE implementations not being able to create an agreed-upon security association at all for many combinations of options, however correctly configured they might appear at either end.