Weak host send/receive may need to be enabled in some situations for Windows servers. An example of this would be if an IP is bound to a loopback adapter and traffic to that loopback IP is routed via a main interface on the server.
To check the weak host send/receive status:
Get-NetIPInterface | ft interfacealias,weakhostreceive,weakhostsend
An example of the output:
[some-srv]: PS C:\Users\admin-user\Documents> Get-NetIPInterface | ft interfacealias,weakhostreceive,weakhostsend
interfacealias WeakHostReceive WeakHostSend
-------------- --------------- ------------
Ethernet 2 Disabled Disabled
isatap.{4E118B16-18B8-493B-B7B7-0DD26020FE3C} Disabled Disabled
Loopback Disabled Disabled
isatap.{9862FB5E-81B3-48BD-9FE0-8E03ADFC33E1} Disabled Disabled
Loopback Pseudo-Interface 1 Disabled Disabled
Ethernet 2 Disabled Disabled
Loopback Disabled Disabled
Loopback Pseudo-Interface 1 Disabled Disabled
To enable or disable:
netsh interface ipv4 set interface "Ethernet 2" weakhostreceive=enabled
netsh interface ipv4 set interface "Ethernet 2" weakhostsend=enabled