user@host# set security utm custom-objects url-pattern url-pattern-name https://www.juniper.net/documentation/us/en/software/junos/utm/topics/t opic-map/security-local-list-antispam-filtering.html

A screen option in the SRX Series device can be used to protect clients connected to the device from a SYN flood attack. Screens are security measures that you can use to protect your network from various types of attacks, including SYN floods. A screen option specifies a set of rules to match against incoming packets, and it can take specific actions such as discarding, logging, or allowing the packets based on the rules.

By default, TCP has a 30-minute idle timeout, and UDP has a 60-second idle timeout. Additionally, known IP protocols have a 30-minute timeout, whereas unknown ones have a 60-second timeout. Setting the inactivity timeout is very useful, particularly if you are concerned about applications either timing out or remaining idle for too long and filling up the session table. According to the Juniper SRX Series Services Guide, this can be configured using the 'timeout inactive' statement for the security policy.

The two correct statements about the Junos OS CLI are that the default configuration requires you to log in as the admin user, and that most Juniper devices identify the root login prompt using the > character. The factory-default login assigns the hostname "juniper" to the device and the root login prompt is usually identified with the % character. More information about the Junos OS CLI can be found in the Juniper Networks technical documentation here:https://www.juniper.net/documentation/en_ US/junos/topics/reference/command-summary/cli-overview.html.