Forum Discussion
Michaelyang
Cirrostratus
CirrostratusIf there is no firewall, the risk of problems
Hello, My architecture is as follows " Clients -> firewall -> F5 -> Server " I would like to ask if it is risky to open all ports in the client->F5 VIP section of the firewall? For example. 445 ...
Michaelyang because the F5 is not configured to listen on 445 in the example you have provided you do not have a risk currently for the backend servers or the F5. The keyword here is currently, it is possible that in the future a vulnerability might exist that does leave your F5 or backend servers vulnerable to an attack and why you should only ever allow the ports you need through and not everything. What is the reasoning for allowing all ports through to the F5 virtual server? If the reasoning here is because someone doesn't want to go allow each port when you start to use it that is an extremely flawed and a huge security risk approach to managing a network. It's best to stick to best practices and not to encourage practices that put your network in a vulnerable security posture.
mihaic
MVP
MVPhere are some best practices for hardening an F5:
https://support.f5.com/csp/article/K53108777
It is not a good idea to open all ports. Never.
Open only ports that you use.
Why do you use a firewall if you open all ports?
Why do you open access to something that does not exist?
If your F5 has no vip on port 445 then it will drop the session.
Unless you have a forwarding VIP that does some routing. And it might get to the backend servers.