Computer can't ping gateway (but other computers can)

Question

We are running Windows Server 2016 and Exchange 2016.
Recently Windows Server 2016 received and installed 4 KBs:
KB4550993 .net 4.8 (from 2020)
KB4530738 .net 4.8 (from 2019)
KB5034119 Cumlative Update (from 1/9/2024 )
KB5033910 .net 4.8 (from 1/9/2024 ) - installed 1/16

After this update the server is unable to contact the gateway. The other servers/computers in the subnet can reach the gateway, and the firewall and the internet.

We have reset the network adapter and it did not fix. We were thinking the switches or the firewall blocking something. but the fact that the other computers on the subnet can reach the gateway shows that the gateway does respond.

Any thoughts? is there somewhere I can check or test why it can't reach the gateway?

Thanks.

Answer 1

Hi,

Thanks for posting!

Firstly, I would suggest checking event logs: Look for any relevant error or warning messages in the Event Viewer on the server. Check the System and Application logs for any network-related errors that could provide clues about the issue.

And if possible, please share your configuration and deploy information of network, it might help to investigate further.

Best Regards,

Karlie

Answer 2

I have seen a host of errors.:

Event 1023 - Perflib
Windows cannot load the extensible counter DLL MSExchangeIS. The first four bytes (DWORD) of the Data section contains the Windows error code.
Windows cannot load the extensible counter DLL ASP.NET_64_2.0.50727. The first four bytes (DWORD) of the Data section contains the Windows error code.
Windows cannot load the extensible counter DLL ASP.NET_2.0.50727. The first four bytes (DWORD) of the Data section contains the Windows error code.

Event 1008 - MSExchange Mitigation Service
An unexpected exception occurred. Diagnostic information:
Exception encountered while fetching mitigations : System.AggregateException: One or more errors occurred. ---> System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.Net.WebException: Unable to connect to the remote server ---> System.Net.Sockets.SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 52.109.20.38:443

Event 3025 MSExchangeApplicationLogic
Scenario: GetKillBit. Failed to download killbit list from OMEX server. Exception: System.Net.WebException: Unable to connect to the remote server ---> System.Net.Sockets.SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 52.111.246.9:443

Event 4999 MSExchange Common
Watson report about to be sent for process id: 15740, with parameters: E12IIS, c-RTL-AMD64, 15.01.2375.034, M.E.Mitigation.Service, unknown, M.E.M.S.C.U.<GetHttpUrlResponseAsync>d__2.MoveNext, System.AggregateException, 366e-dumptidset, unknown.
ErrorReportingEnabled: True

I assume that the socket errors (1008, 3025) are trying to get out to the internet; so since the computer get to get to the internet, these errors would appear

Here's what I can share about our network. We have vlans and they all point to switches and point to a firewall. The email server is on a vlan where the other computers on the vlan can reach the internet. but the email can not. Other than the 4 KB updates (listed in original post). we don't believe anything else was changed. The fact that the other computers on the same vlan can reach the switches and firewall and internet seem to indicate that the vlan is OK. and the problem is on this one server; it cannot reach the firewall.

Hope that helps.