ssh: connect to host XX.XX.XX.XX port 22: Connection refused while connecting to Guest OS on Virtual Box

Issue:
While connecting from Windows - 10 to Guest OS - Oracle Linux -7.1  on Oracle Virtual Box - 5.2, you may get the below error.
ssh: connect to host XX.XX.XX.XX port 22: Connection refused


shaikprod@shaikprod ~
$ ping 192.168.56.1

Pinging 192.168.56.1 with 32 bytes of data:
Reply from 192.168.56.1: bytes=32 time<1ms TTL=128
Reply from 192.168.56.1: bytes=32 time<1ms TTL=128
Reply from 192.168.56.1: bytes=32 time<1ms TTL=128
Reply from 192.168.56.1: bytes=32 time<1ms TTL=128

Ping statistics for 192.168.56.1:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 0ms, Average = 0ms

shaikprod@shaikprod ~
$ ssh 192.168.56.1
ssh: connect to host 192.168.56.1 port 22: Connection refused

shaikprod@shaikprod ~
$ ssh 192.168.56.1
ssh: connect to host 192.168.56.1 port 22: Connection refused



Fix:
Enable port forwarding on the NAT -Network from the Oracle Virtual Box

How to change SCAN VIPs in 11gR2

Below process is testing and worked when the SCAN vips are configured via the DNS.

Backup:
Hosts file
ocrconfig -manualbackup
 voting disks using "dd"

following command can be used:
$ nslookup dbhost-sv1

Name:   dbhost-sv1.mydomain.com
Address: 10.ns.ip.133
Name:   dbhost-sv1.mydomain.com
Address: 10.ns.ip.135
Name:   dbhost-sv1.mydomain.com
Address: 10.ns.ip.134


Stop the scan resources:

# $GRID_HOME/bin/srvctl stop scan_listener
# $GRID_HOME/bin/srvctl stop scan
# $GRID_HOME/bin/srvctl status scan
>srvctl status scan
SCAN VIP scan1 is enabled
SCAN VIP scan1 is running on node dbhostdb02
SCAN VIP scan2 is enabled
SCAN VIP scan2 is running on node dbhostdb01
SCAN VIP scan3 is enabled
SCAN VIP scan3 is running on node dbhostdb01



Confirm whether they are really down:


Make the change in the DNS:
# nslookup dbhost-sv1  << should be new IPs
>/usr/sbin/nslookup dbhostdb01-sv1


Name:   dbhostdb01-sv1.mydomain.com
Address: 10.ip.ip.156
Name:   dbhostdb01-sv1.mydomain.com
Address: 10.ip.ip.158
Name:   dbhostdb01-sv1.mydomain.com
Address: 10.ip.ip.157

Now tell CRS to update the SCAN VIP resources:
# $GRID_HOME/bin/srvctl modify scan –n dbhost-sv1  ( This will refresh the new IPs for SCAN)
# $GRID_HOME/bin/srvctl config scan ( verify the new IP's are reflected. )
>srvctl config scan
SCAN name: dbhostdb01-sv1, Network: 1/10.ip.ip.0/255.255.255.0/bge0
SCAN VIP name: scan1, IP: /dbhostdb01-sv1.mydomain.com/10.ip.ip.156
SCAN VIP name: scan2, IP: /dbhostdb01-sv1.mydomain.com/10.ip.ip.158
SCAN VIP name: scan3, IP: /dbhostdb01-sv1.mydomain.com/10.ip.ip.157



# $GRID_HOME/bin/srvctl status scan
>srvctl status scan
SCAN VIP scan1 is enabled
SCAN VIP scan1 is running on node dbhostdb02
SCAN VIP scan2 is enabled
SCAN VIP scan2 is running on node dbhostdb01
SCAN VIP scan3 is enabled
SCAN VIP scan3 is running on node dbhostdb01


# $GRID_HOME/bin/srvctl start scan
# $GRID_HOME/bin/srvctl start scan_listener

Reference:952903.1

find voting disk locations

>crsctl query css votedisk
##  STATE    File Universal Id                File Name Disk group
--  -----    -----------------                --------- ---------
 1. ONLINE   1f8910b4b32d4f45bfa885ff25de0c3e (/dev/oracle/ocr_disk_1) [GRID_DATA_01]
 2. ONLINE   872ae1a0294b4fbabf8aa4e86d9c1901 (/dev/oracle/ocr_disk_2) [GRID_DATA_01]
 3. ONLINE   7c69fababb9a4fcfbf82d3e72ad516f6 (/dev/oracle/spfile+ASM.ora) [GRID_DATA_01]
Located 3 voting disk(s).

11gR2 RAC -Find configured private and public interfaces on the cluster

Clusterware uses the interconnect for cluster synchronization (network heartbeat) and daemon communication between the the clustered nodes. This communication is based on the TCP protocol.
RAC uses the interconnect for cache fusion (UDP) and inter-process communication (TCP). Cache Fusion is the remote memory mapping of Oracle buffers, shared between the caches of participating nodes in the cluster. The volume and traffic patterns of this type of data, shared between nodes can vary greatly depending on the applications.

Protocol
Unix and Linux

cluster interconnect IPC version:Oracle UDP/IP (generic)

Windows:

cluster interconnect IPC version:Oracle 9i Winsock2 TCP/IP IPC

in 10gR1 x$ tables x$ksxpia and x$skgxpia provide the same information.


>srvctl config nodeapps -a

The value of the private interconnect for an instance can be identified using

1. The views V$CLUSTER_INTERCONNECTS and V$CONFIGURED_INTERCONNECTS
   
   V$CLUSTER_INTERCONNECTS displays one or more interconnects that are being used for cluster communication.
   
   V$CONFIGURED_INTERCONNECTS displays all the interconnects that Oracle is aware of. This view aims to answer the question on where Oracle found the information about a specific interconnect.
   
   These views are not available in Oracle 10g 10.1.
   
   
2. The alert.log
   
   • CLUSTER_INTERCONNECTS parameter is set
   • Value read from Cluster Registry

olsnodes -n -p can be used to identify the private node name.

You may also check the private node name in the ocrdump output.

ocssd.log has a line with clssnmClusterListener

References:
NOTE:283684.1 - How to Change Interconnect/Public Interface IP or Subnet in Oracle Clusterware
NOTE:341788.1 - Recommendation for the Real Application Cluster Interconnect and Jumbo Frames
NOTE:368464.1 - How to Setup IPMP as Cluster Interconnect