10-03-2008 10:27 AM - edited 03-11-2019 06:52 AM
Hello
I'm switching from a checkpoint firewall to an asa5500. I have 2 question's that i hope don't sound to stupid. In writing rules first do i apply the rule to the interface closest to the source device as an incoming rule, and second do i need to write reverse rules also? Thank you in advance.
10-03-2008 11:10 AM
Generally you'd want to make your outside interface "security 0", create an access-list and then bind it to the interface using the access-group command.
For simplicity you don't need an ACL on the inside interface which would be "security 100". All traffic is permitted from high to low security by default.
10-03-2008 01:01 PM
thanks for the reply.
Let me clarify some. We start by only allowing all our internal systems a limited amount of out bound services so from there i need to allow anything that this or that system may need to use. Here is an example of what id need to do:
I have a group of internal servers that need to connect to a group of external servers, remembering that above i have already only allowed certain traffic such as 80 & 443 out using the deny any any to block everything else. here is an example of the rule to allow the two server groups to communicate.
access-list inside_access_in extended permit tcp object-group Internal_Secure-FTP-Client-Systems object-group External_Secure-FTP-Servers
I am trying to make sure my logic isn't flawed. And will the fact that the return traffic is essentially established do I need reverse rules or is this not needed.
Thanks for the help.
Mike
10-03-2008 01:20 PM
First of all, welcome to Cisco's world. You're
going to a platform with excellent management
capability (Checkpoint) to a platform that is
not that great in terms of management
capability (Cisco).
That being said, Your logic is good.
Furthermore, I also put in stealth and clean-up
rules, since you're familiar with Checkpoint,
on the ASA for better troubleshooting if I
were you:
access-list inside_access deny ip any Firewall _Inside_ip_address log
access-list inside_access deny any any log
access-list outside_access deny ip any Firewall_outside_ip_address log
access-list outside_access deny ip any any log
Easy right?
10-06-2008 07:56 PM
Mike,
your ACL
"access-list inside_access_in extended permit tcp object-group Internal_Secure-FTP-Client-Systems object-group External_Secure-FTP-Servers"
will allow all 65356 tcp ports for your external users. In order to open only certain group of ports, you need to modify your ACL like
"access-list inside_access_in extended permit tcp object-group Internal_Secure-FTP-Client-Systems object-group External_Secure-FTP-Servers object-group ports-for-internal-to-external-server"
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