Three Digit Extensions to Avoid Using With an Internal Numbering Plan

Question

Which three-digit extension numbers are reserbed and should not be assigned to users or services?  

Applies To

• 8x8 Work

• 8x8 Contact Center

Answer

Three digit extension numbers that are reserved for 8x8 services and should not be assigned to any user or object. This includes, but not limited to, Ring Groups, Auto Attendants, etc.  We recommend using a minimum of 4-digit extension numbers for internal numbering plans. If this is not possible, and 3-digit extension numbers are required, avoid using any of the following extension numbers for internal numbering plans. Otherwise, issues may occur.  

3-Digit Extensions

We recommend against using any of the following 3-digit combinations as extension numbers for internal numbering plans.  

4-Digit Extensions

We also recommend against using any of the following 4-digit combinations as extension numbers for internal numbering plans.  

6-Digit Extensions

We also recommend against using any of the following 6-digit combinations as extension numbers for internal numbering plans.