Hi everyone!
Recently i have faced a situation that made me find out a very nice and useful command that helped me a lot, and i hope it comes to help you guys as well, and it’s named:
nc
Situation: We have a replicated environment from one datacenter to another (Using Golden Gate), where the ETL happens. So basically is:
Datacenter 1 (root data)
Replicates to datacenter 2 (transforming the data)
that replicates to datacenter 3 (production itself)
In Datacenter level 2, we have a dataguard configured. So then came the question:
- What if we need to do the switchover to the standby environments?
- Will we gonna have everything we need properly set up for the replication?
- How are we going to test the ports if nothing is up in there? Aren’t we gonna get “connection refused”?
Calm down! There is a very nice workaround for this.
All you need to do is install the nc command as root (if it is not installed already):
yum install nc
Then execute it as follows, on the server you wanna test:
nc -l
example:
I wanna make sure that on the standby server the port 7809 (Golden Gate MANAGER port) is open. On the standby server you run:
nc -l 7809
Then, from a remote server, you are going to be able to connect through a simple telnet command:
telnet server.domain port
example:
telnet standby.company.com 7809
ON PRACTICE:
- Try the telnet from the remote server to the standby:
remoteserver {/home/oracle}: telnet standby.server 7809
Trying 192.168.0.10…
telnet: connect to address 192.168.0.10: Connection refused
- Then we start the fake service on the standby server!
standby.server {/home/oracle}: nc -l 7809
- And try the telnet again:
remoteserver {/home/oracle}: telnet standby.server 7809
Trying 192.168.0.10…
Connected to standby.server.
Escape character is ‘^]’.
Cheers!
Rafael.