Karan Rajpoot Oracle DBA Blog's

                                                        Destination Host Unreachable in Linux Error: -  icmp_seq=2 Destination Host Unreachable Cause: - When you are trying to ping Linux machine from one node to another node then you may face issue "destination host unreachable", the reason behind this issue is the selection of network while creation of Linux machine. Solution: - To resolve this issue you need to select the proper network selection. Example: - In this case, there are two machine prod and dr, When I was tried to ping dr machine from prod then I faced below issue. I checked so many things like firewall, etc/hosts file entries and so on, but didn't get resolution then, at last, I checked my network configuration and found it was set as NAT. I have changed the Network from NAT to the host-only adapter and then tried again finally, that issue has been resolved. Before changing the network from NAT to Host-only adapter. [root@prod Desk

Error 1) [oracle@prod ~]$ dbca No protocol specified Error 2) [oracle@prod ~]$ netca Oracle Net Services Configuration: No protocol specified Error: null Check the trace file for details: /u01/app/oracle/cfgtoollogs/netca/trace_OraDb11g_home1-1901166PM3102.log Oracle Net Services configuration failed.  The exit code is 1 Solution Step 1) login as root user Step 2) run command xhost + this command allows you to use any graphical tool Example: - [root@prod Desktop]# xhost + access control disabled, clients can connect from any host Step 3) Now again run graphical tool utility command, that issue will get resolved now. [oracle@prod ~]$ dbca