I can no longer ping outside our network when I switch our server to a static IP. The backstory:
The server runs Windows Server 2016 Essentials with dual Broadcom NetXtreme Gigabit NICs. It was previously configured with one NIC on DHCP (192.168.1.228
), one on a static IP (192.168.1.251
). We were having sporadic network performance issues, and when I reviewed the server's logs I noticed frequent errors saying:
A duplicate name has been detected on the TCP network.
The issue appeared to be the fact that the NICs had different IP addresses but the same server name. I set up NIC teaming for the two NICs with Default VLAN membership. Running nbtstat -n
showed we had one dynamic IP for the NIC team, and network performance seemed to have improved.
I then discovered that one of our CNC machines was not able to access the server via its mapped network drive, which was pointing to the old static IP (192.168.1.251
) of one of the NICs from before it was teamed. The CNC machine is on a separate subnet:
>ipconfig /all
Windows IP Configuration
Host Name . . . . . . . . . . . . : PPC01_101
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
Ethernet adapter LAN:
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Intel(R) Ethernet Connection I219-LM
Physical Address. . . . . . . . . : 20-46-A1-02-E1-7B
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::d178:76cf:1b17:58bc%13(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.100.101(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.100.200
DHCPv6 IAID . . . . . . . . . . . : 270550689
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-20-A2-4A-B0-00-05-B7-E6-F6-6E
DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1
fec0:0:0:ffff::2%1
fec0:0:0:ffff::3%1
NetBIOS over Tcpip. . . . . . . . : Enabled
The original vendor set up our HP 2920-48g switch to allow the CNC machine only to communicate with 192.168.1.251
, so I can't ping the server name from that machine. I figured I would resolve the problem by changing the server's NIC team to a static IP of 192.168.1.251
. However, when I change from DHCP to the static IP I can no longer ping outside our network from the server.
I can ping outside the network when on DHCP, but can't access the server from the CNC machine:
>ipconfig /all
Ethernet adapter Server NIC Team:
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Microsoft Network Adapter Multiplexor Driver
Physical Address. . . . . . . . . : 10-98-36-AE-12-93
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::99cf:7507:898:412a%11(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.1.228(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.1.1
DHCP Server . . . . . . . . . . . : 192.168.1.1
DHCPv6 IAID . . . . . . . . . . . : 185636918
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-20-25-75-36-10-98-36-AE-12-93
DNS Servers . . . . . . . . . . . : 66.155.216.122
207.59.153.242
NetBIOS over Tcpip. . . . . . . . : Enabled
I can't ping outside the network when I set a static IP:
>ipconfig /all
Ethernet adapter Server NIC Team:
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Microsoft Network Adapter Multiplexor Driver
Physical Address. . . . . . . . . : 10-98-36-AE-12-93
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::99cf:7507:898:412a%11(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.1.251(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.1.1
DHCPv6 IAID . . . . . . . . . . . : 185636918
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-20-25-75-36-10-98-36-AE-12-93
DNS Servers . . . . . . . . . . . : 66.155.216.122
207.59.153.242
NetBIOS over Tcpip. . . . . . . . : Enabled
I still get the same problem when I temporarily turn off Windows Firewall on the server.