PBX GUI - Configuring Multiple Express for Lync appliances on Same Subnet

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Warning: When using multiple Express for Lync servers in the same subnet the steps below are required. This is because MAC address conflicts will occur. These steps should only be followed on the second unit (additional units as well), Do not do this on the first Express for Lync appliance.

1) Power Down All VMs Running in Hyper V

2) Go into the settings of each VM and do disconnect it from the network. To do this go into the Network Adapter Settings and change the Virtual switch to Not connected. Repeat this for every Network Adapter in each VM except the Transcoding Network Adapter in the SBC VM.

3) Once all Network Adapters are in the Not connected state go into the Virtual Switch and remove both the External Interface and the Internal Interface.

4) Go to MAC Address Range and change the range of MAC addresses. To do this change the 4th octet to to the original value +1 as shown below. This will ensure your network interfaces obtain different MACs then the other Express for Lync on the subnet.

5) Go to New virtual network switch and select External then click Create Virtual Switch.

Name the switch External and select 82579LM as the network connection. Click Apply to save changes.

6) Go to New virtual network switch and select External then click Create Virtual Switch.

Name the switch External and select 82574L as the network connection. Click Apply to save changes.

7) Add the new Internal and External interfaces to all of the VMs. To do this repeat step#2 but change the interface to External or Internal.

8) [SBC VM Only] If you are using the SBC power up the VM. Then connect to the console of the SBC. Run the command ifconfig eth0 and note down the MAC address. Do this again for eth2 ifconfig eth2.

9) Edit the file /etc/sysconfig/network-scripts/ifcfg-eth0 and change the HWADDR to the MAC address recorded in the previous step. Do this for both eth0 and eth2 (/etc/sysconfig/network-scripts/ifcfg-eth2).

10) Restart the network interfaces using the command /etc/init.d/network restart and you now should see IPs assigned to eth0 and eth2.

11) At this point you should disable the External and Transcoding interfaces on the host as shown below.

12) Now both Express for Lync units will work well in the same subnet.