I am developer not an administrator. That's why i am here to get expert's views.
My setup is of webform of 5 windows 2008 servers behind Cisco ASA5505 firewall.
I have written a small application (say MyServer.exe) that listen on a specific port (say 12345). Client application send message to MyServer.exe as encrypted strings that is later decrypted on server.
MyServer.exe application has to run only on 2 servers out of 5.
a. On those 2 servers Windows firewall i have created an inbound rule for the program MyServer.exe for the port 12345.
b. On Cisco firewall i have also opened port 12345.
c. Port 12345 is already blocked on remaining servers.
Is it safe combination or i need to do anything else to strengthen the security?
It is possible to open port in Cisco firewall for specific application or for Specific servers (behind the Cisco firewall) only so it should open port only for 2 servers where i have to run that application and leave that port closed for remaining servers.