vCenter VAMI Backup Location Change Fails with NT_STATUS_IO_TIMEOUT

Products

• VMware vCenter Server

Issue/Introduction

• While attempting to change the backup location in the VMware vCenter Server Appliance Management Interface (VAMI) using the SMB protocol, the operation fails with the following error: "General system error reported by backup server"
• In the /var/log/vmware/applmgmt.log, the following timeouts are observed:

YYYY-MM-DDTHH:MM:SS PM UTC [8341] ERROR: plugins.SMBClientStorageIOLib: Command failed with error: NT_STATUS_IO_TIMEOUT.
YYYY-MM-DDTHH:MM:SS AM UTC [11707]ERROR:plugins.SMBClientStorageIOLib:smb cmd failed. RC: 1, Err: do_connect: Connection to <REDACTED_IPS> failed (Error NT_STATUS_IO_TIMEOUT)
YYYY-MM-DDTHH:MM:SS AM UTC [11718]ERROR:plugins.SMBClientStorageIOLib:smb cmd failed. RC: 1, Err: do_connect: Connection to <REDACTED_HOSTNAMES> failed (Error NT_STATUS_IO_TIMEOUT)

• Running manual SMB verification commands fails with connection timeouts:

/usr/bin/smbclient //<REDACTED_HOSTNAMES>/<share> -U <user> -m SMB3 --option="client min protocol=SMB2" --option="client max protocol=SMB3" -c "ls" 
>>>>do_connect: Connection to <REDACTED_HOSTNAMES> failed (Error NT_STATUS_IO_TIMEOUT)

• Testing port 445 connectivity via nc shows the port is not reachable:

root@vcenter[ ~ ]# nc -zv <REDACTED_IPS> 445
<REDACTED_HOSTNAMES> [<REDACTED_IPS>] 445 (microsoft-ds): Connection timed out.

Environment

vCenter server 7.x

vCenter server 8.x

Cause

SMB communication over port 445 is blocked at the network level between the vCenter Server and the target backup server.

Resolution

1. Engage your network administration team to review firewall policies and routing paths.

2. Ensure TCP port 445 is open and allows bi-directional communication between the vCenter Server and the SMB backup server.

Additional Information

If necessary, perform a network packet capture to gain a better understanding of the issue.