Error while configuring legacy vSphere Replication for a virtual machine : Failed to create NFC connection to ##.##.##.###"
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Error while configuring legacy vSphere Replication for a virtual machine : Failed to create NFC connection to ##.##.##.###"

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Article ID: 444603

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Updated On:

Products

VMware vSphere ESXi

Issue/Introduction

  •  Following error appears in the SRM  UI when attempted to configure the replication using legacy:

A replication error occurred at the vSphere Replication Server for replication 'VM#'. Details: 'Error for (diskId: "RDID-########-####-####-####-############"), (hostIP: "##.##.##.###"), (flags: on-disk-open, retriable): Error connecting to host.; Set error flag: retriable; Failed to create NFC connection to ##.##.##.###, 902 via ip Any: Failed to connect to server ##.##.##.###:902; establish nfc connection on host-##; Tried operation 4 times, giving up.; Probing disk capacity.; While getting host capabilities for disk. (native snapshot hint = false); Failed to open disk, couldn't get disk type/capabilities; Set error flag: on-disk-open; Tried operation 4 times, giving up.; Failed to open replica (/vmfs/volumes/########-####-####-####-############/VM#/VM#.vmdk); Failed to open activeDisk (GroupID=GID-7########-####-####-####-############) (DiskID=RDID-########-####-####-####-############); Can't create replica state (GroupID=GID-########-####-####-####-############) (DiskID=RDID-########-####-####-####-############); Cannot activate group. Loading disks from database (GroupID=GID-########-####-####-####-############) ; Connecting to group GID-########-####-####-####-############'.

Environment

VMware vSphere Replication 9.x
VMware vSphere ESXi 8.x

Cause

Network File Copy (NFC) traffic on TCP port 902 is blocked bidirectionally between the vSphere Replication appliance and the ESXi hosts at the recovery site.

  • vSphere Replication appliance /var/log/vmware/hbrsrv.log contains timeouts:
2026-06-04T10:11:30.002+10:00 info hbrsrv[01304] [Originator@6876 sub=Libs opID=########-####-####-####-############-HMS-2##] CnxOpenTCPSocket: Timed out connecting to server ##.##.##.###:902: Operation now in progress
2026-06-04T10:11:30.002+10:00 info hbrsrv[01304] [Originator@6876 sub=Libs opID=########-####-####-####-############-HMS-2##] CnxAuthdConnect: Returning false because CnxAuthdConnectTCP failed
####-####-####-####-############-HMS-2##] Cnx_Connect: Returning false because CnxConnectAuthd failed
2026-06-04T10:11:30.002+10:00 info hbrsrv[01304] [Originator@6876 sub=Libs opID=########-####-####-####-############-HMS-2##] [NFC ERROR]NfcNewAuthdConnectionEx: Failed to connect: Failed to connect to server ##.##.##.###:902
2026-06-04T10:11:30.002+10:00 info hbrsrv[01304] [Originator@6876 sub=Libs opID=########-####-####-####-############-HMS-2##] [NFC ERROR]NfcEstablishAuthCnxToServer: Failed to create new AuthD connection: Failed to connect to server ##.##.##.###:902
2026-06-04T10:11:30.002+10:00 info hbrsrv[01304] [Originator@6876 sub=Libs opID=########-####-####-####-############-HMS-2##] [NFC ERROR]Nfc_BindAndEstablishAuthdCnx3: Failed to create a connection with server ##.##.##.###: Failed to connect to server ##.##.##.###:902
2026-06-04T10:11:30.003+10:00 error hbrsrv[01304] [Originator@6876 sub=Main opID=########-####-####-####-############-HMS-2##] HbrError for (hostIP: "##.##.##.###"), (flags: retriable, already-retried) stack:
2026-06-04T10:11:30.003+10:00 error hbrsrv[01304] [Originator@6876 sub=Main opID=########-####-####-####-############-HMS-2##]    [0] Error connecting to host.
2026-06-04T10:11:30.003+10:00 error hbrsrv[01304] [Originator@6876 sub=Main opID=########-####-####-####-############-HMS-2##]    [2] Failed to create NFC connection to ##.##.##.###, 902 via ip Any: Failed to connect to server ##.##.##.###:902
2026-06-04T10:11:30.003+10:00 error hbrsrv[01304] [Originator@6876 sub=Main opID=########-####-####-####-############-HMS-2##]    [3] establish nfc connection on host-###
2026-06-04T10:11:30.003+10:00 error hbrsrv[01304] [Originator@6876 sub=Main opID=########-####-####-####-############-HMS-2##]    [5] Set error flag: already-retried
2026-06-04T10:11:30.003+10:00 error hbrsrv[01304] [Originator@6876 sub=Main opID=########-####-####-####-############-HMS-2##]    [6] Failed to open file /vmfs/volumes/########-####-####-####-############/VM#/VM#/hbrgrp.GID-########-####-####-####-############.txt, couldn't create NFC session
 

Resolution

  1. Coordinate with the network security team to allow bidirectional traffic on TCP Port 902 (NFC traffic) between the vSphere Replication appliance and all ESXi hosts at both the primary and recovery sites.

  2.  Run the following command from the vSphere Replication appliance shell to test connectivity to the destination ESXi host:

     nc -zv <Destination-ESXi-IP> 902

  3. Reconfigure the replication for the affected virtual machines using legacy.

Additional Information

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