In certain circumstances, the firewall may not see the three-way handshake for a particular flow (i.e. You can configure logs to view traffic for Mail Server.A TCP connection begins with a three-way handshake (SYN, SYN-ACK, ACK), and typically ends with a two-way exchange (FIN, ACK). In this way you can configure firewall rule in Juniper SRX firewall. Similarly, you can create firewall rule to pass any traffic from Trust-Zone to Untrust-Zone. To view the firewall rule, type show command in the same hierarchy. We want to permit the traffic and log each sessions. Since the traffic is coming from Untrust-Zone we need to match any source-addres and destination-address of MailServer then specify the condition. We need to create firewall rule for traffic coming from Untrust-Zone to Trust-Zone. Step 4: Create Firewall Rule to Allow Traffic from Internet destined for Mail Server We can see the address book and interface at this zone in screenshot shown below. You can type show command to view the configuration for Trust-Zone till now. To create address type following command in hierarchy. We need to create address book of Mail Server that we have in the Trusted-Zone. We can’t simply type IP address in the rule. To match source and destination IP address in the firewall rule we need to create an address book. Step 2: Create Address Book in Trust Zone You can see the configured security zones by typing Show Command under hierarchy The command is, set security-zone interfaces. We need to assign interface ge-0/0/1 to Untrust-Zone and interface ge-0/0/0 to Trust-Zone. Step 1: Assign Interface to Security Zone We will assume that in the following scenario NAT (Network Address Translation) has been configured properly. We want mail traffic to flow in and out of two security zones, untrust and trust. We want users from Internet to be able to access the Mail Server. We have a Mail Server hosted in the internal network or the trust-zone. We have a scenario as shown in the diagram below. For example, if a policy named My Policy matches source address of x.x.x.x/x and destination address of y.y.y.y/y and application of FTP then we can define condition to permit and log the traffic. Various conditions can be defined like, permit, deny, log, reject and count. Condition: Conditions are whether to allow/deny the traffic.Source address, destination address and application are mandatory match conditions. Application: This is a protocol or service that is allowed/denied by the rule.Address book are created in zones to match address in the rule. For example, a policy named My Policy matches source address of x.x.x.x/x and destination address of y.y.y.y/y then we define a condition to allow or block the traffic. These source address and destination address are used to match the condition. IP Address: IP address define source network or hosts and destination network or hosts.Note: – Cisco calls firewall rule, Juniper calls security policy which is basically the same thing. For example, if I want to allow traffic from Untrust Zone to Trust Zone then I would name my policy as Internet Rule or Internet Policy. Policy: This is a policy name that is used to define the firewall rule (policy).Firewall policies (rules) need source zone and destination zones defined prior defining the firewall rule.
You can create zone name as Accounting Zone for firewall interface connected to accounting switch and so on. Interface connected to the Internet is usually named Untrust Zone, interface connected to the internal network is usually called Trust Zone. Each interface is assigned to a security zone. Security Zones: Security zones are logical boundary.Elements of Juniper firewall rules are: – Here, I will use command line to demonstrate firewall rule creation.īefore configuring firewall rules, there are some basic terminologies that are necessary to understand. You can configure firewall rule in Juniper SRX using command line or GUI console. SRX firewall inspects each packets passing through the device.
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Juniper SRX series firewall products provide firewall solutions from SOHO network to large corporate networks. Juniper firewalls are capable of filtering traffic based on source/destination IP address and port numbers. Firewall rules or also called security policies are methods of filtering and logging traffic in the network.