Symptom
In some cases, you need to create an External Virtual Switch and bind it to a wireless NIC. However, you may face network issues with this configuration.
Solution
To resolve the issue, we need to set static IP address for the virtual adapter and VMs that connect to it.
Analysis
In this part, we setup a test and explain why we need to set static IP address.
1. There is a wireless NIC with MAC Address 40-F0-2F-35-E0-5C in the Hyper-V Host. (Figure 1)
![Capture]()
Figure 1
2. Create an external virtual switch named “EX” and bind it to the wireless. (Figure 2)
![Configuration]()
Figure 2
3. Connect to a wireless network and the host gets a dynamic IP 192.168.0.102. (Figure 3)
![dhcp_host]()
Figure 3
4. In the Hyper-V Host, we use network monitor
to capture the packets on the physical wireless NIC when ping the gateway 192.168.0.1. (Figure 4)
![monitor_configure_wifi]()
Figure 4
5. We can see the source MAC and IP address are both correct. (Figure 5)
![monitor_ping_host]()
Figure 5
6. Connect VM “test2” to the external virtual switch “EX” and the MAC address is 00-15-5D-00-64-04. (Figure 6)
![vm_configure]()
Figure 6
7. Capture the DHCP packets on physical wireless NIC and there is no packet was sent out from “test2” (MAC address: 00-15-5D-00-64-04) (Figure 7)
![dhcp_host]()
Figure 7: DHCP packets on physical wireless NIC
8. From the packets captured in “test2”, the DHCP Offer packet included the IP address 192.168.0.102. However, it was assigned to the Hyper-V Host and thus caused IP confliction.
![dhcp_vm2]()
Figure 8: DHCP packets on virtual NIC of test2
9. We set a static IP address (192.168.0.99) for “test2”. From the Arp table, we can find that both IP address bind to the Mac Address of the Hyper-V Host. (Figure 9).
![C]()
Figure 9
Based on the above test, we may come to a conclusion, if you face this problem, you may need to set static IP for the virtual NIC.
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