Hab’s Blab

 

Environment:

Skype for Business Server 2015

• Front-end Server
• Edge Server

Operating System

• Windows Server 2016

Issue:

During a Skype for Business Edge deployment where we had the 2 Network Interface Cards (NICs) one for 1 Internal DMZ and 1 for the External DMZ, both NICs were provided IP Addresses on the appropriate network:

External DMZ:

• IP: 192.168.2.10
• SM: 255.255.255.0
• GW: 192.168.2.1

Internal DMZ:

• IP: 192.168.3.10 (Duplicate)
• SM: 255.255.255.0

However when you performed an IPConfig /All, it also showed an additional IP on the Internal DMZ NIC, but the Internal DMZ NIC wasn’t listening on its IP.

• IP: 169.254.51.14 (Preferred)
• SM: 255.255.0.0

Resolution:

In order to get the NIC card listening on the correct IP and remove the 169.254.x.x address, we need to modify the registry.

1. Open Registry Editor and Browse to : HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Paramenters
2. Right Click on Parameters -> New DWORD (32 Bit)
   1. Name: ArpRetryCount
   2. Value:0
3. Exit Registry Editor
4. Reboot the Edge Server
5. Once the server comes up the NIC will be listening on the correct IP Address.