- Create address book entries for the source and destination addresses.
- Create the custom application if no pre-defined applications encompass the protocol or ports needed.
- Create a security policy to permit the traffic using the custom application.
1. Create the address book entries for the source and destination addresses
From J-Web:- Go to Configuration >Security > Policy Elements.
- To add an address book entry for each zone, click on Address Books.
- Click on the zone for which you would like to add an address book entry (example: zone
trust). - If address book entry required does not exist, then click Add....
- In the Address Name field specify a name (example:
local- net).
Note: The name must be a string beginning with a letter and consisting of letters, numbers, dashes and underscores. - In IP Address/Prefix, enter the IP address/subnet mask (example:
192.168.10.0/24). or
in DNS Name, specify a fully qualified domain name.
Note: The J Series or SRX Series device must have a working DNS server configured to resolve the domain name. - Click OK.
- Repeat steps 3-7 for zone
untrust, Address Book entryremote-net. Click OK again to return to the Security Policies screen.
set security zones security-zone trust address-book address local-net 192.168.10.0/24
set security zones security-zone untrust address-book address remote-net 192.168.20.0/24
2. Create a custom application
From J-Web:- From Configuration > Security > Policy Elements screen, click on Applications.
- Select Custom-Applications tab.
- Click Add...
- Specify Application Name (example:
tcp1500), then click(plus box) for Configure top level options.
- Click on Match IP protocol, pull down, and choose
tcp. - Enter
1500in the free-form field for Destination port (not the pull-down field). Click OK.
Note: Since the application can use any source port, it is not necessary to also specify a source port for the application. - Click OK again to return to the Security Policies screen.
set applications application tcp1500 protocol tcp
set applications application tcp1500 destination-port 15003. Create a security policy to permit the traffic, using the custom application
From J-Web:- From Configuration > Security > Policy screen, click Apply Policy.
- In
Zone Direction, select From Zonetrustand To Zoneuntrust. - Click Add a Policy.
- Specify Policy Name (example:
policy-tr-unt), then click - Select Source Address Book
local-netobject on the right side and click(left arrow) to add to the Matched list.
- Select Destination Address Book
remote-netobject and click - Select Application
tcp1500and click - For
Policy Action, select Permit from the pull-down menu. - Click OK to commit changes. Then click OK again to return to main policy configuration screen.
set security policies from-zone trust to-zone untrust policy policy-tr-unt match source-address local-net
set security policies from-zone trust to-zone untrust policy policy-tr-unt match destination-address remote-net
set security policies from-zone trust to-zone untrust policy policy-tr-unt match application tcp1500
set security policies from-zone trust to-zone untrust policy policy-tr-unt then permit
The ordering of policies is important. J Series or SRX Series devices
will perform policy lookup from top to bottom until a match is found.
At that point no further policy lookup occurs. Therefore if a deny all policy exists, then be sure that the policy created is above the deny all policy. If not, then the policy will never be reached. To re-arrange policy order, use the Move up or down option in the Security Policies screen in J-Web or the insert command in CLI. Examples:
Here are two custom applications created for TCP ports 5000 and 5001:
applications {
application tcp_port_5000 {
protocol tcp;
destination-port 5000;
}
application tcp_port_5001 {
protocol tcp;
destination-port 5001;
}
}A security policy to and from the desired security zones is created. Below, we can see the custom application used:
[security policies]
from-zone inside to-zone outside {
policy telnet_100 {
match {
source-address any;
destination-address host_public;
application tcp_port_5000;
}
then {
permit
}
}
policy telnet_101 {
match {
source-address any;
destination-address host_public;
application tcp_port_5001;
}
then {
permit
}
}
}
