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{ "lLangCode": "en", "lName": "English", "lCountryCode": "us", "transcode": "en_US" }
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Screen Options for Tenant Systems

date_range 28-Nov-23

Screen options for Tenant Systems on SRX Series Firewalls prevent attacks as , such as IP address sweeps, port scans, denial of service (DOS) attacks, ICMP, UDP, and SYN floods as same as Logical Systems. For more information, see the following topics:

Understanding Tenant System Screen Options

Using screen options, the device secures a zone by inspecting, and then allowing or denying all connection attempts that require crossing an interface bound to that zone. Junos OS applies the firewall policies, which can contain the content filtering and the IDP components to the traffic that passes the screen filters. All screen options that are available on the device are also available in each tenant system.

Starting in Junos OS Release 18.3R1, the screen options that are supported for logical systems are extended to tenant systems.

Example: Configuring Screen Options for a Tenant System

This example shows how to configure screen options for a tenant system.

Requirements

Before you begin:

Overview

Using screen options, the security device can protect against the different internal and external attacks for security zones. You can limit the number of concurrent sessions to the same destination IP address in a tenant system. Setting a destination based session limit can ensure that Junos OS allows only an acceptable number of concurrent connection requests—no matter what the source—to reach any one host. When the number of concurrent connection requests to an IP address surpasses the limit, Junos OS blocks further connection attempts to that IP address.

Configuration

Procedure

CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, copy and paste the commands into the CLI at the [edit] hierarchy level, and then enter commit from configuration mode.

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set tenants TN1 security screen ids-option jscreen limit-session destination-ip-based 80
set tenants TN1 security screen ids-option jscreen icmp ip-sweep threshold 1000
set tenants TN1 security screen ids-option jscreen icmp fragment
set tenants TN1 security screen ids-option jscreen icmp large
set tenants TN1 security screen ids-option jscreen icmp flood threshold 200
set tenants TN1 security screen ids-option jscreen icmp ping-death
set tenants TN1 security screen ids-option jscreen ip bad-option
set tenants TN1 security screen ids-option jscreen ip stream-option
set tenants TN1 security screen ids-option jscreen ip spoofing
set tenants TN1 security screen ids-option jscreen ip strict-source-route-option
set tenants TN1 security screen ids-option jscreen ip unknown-protocol
set tenants TN1 security screen ids-option jscreen ip tear-drop
set tenants TN1 security screen ids-option jscreen tcp syn-fin
set tenants TN1 security screen ids-option jscreen tcp tcp-no-flag
set tenants TN1 security screen ids-option jscreen tcp syn-frag
set tenants TN1 security screen ids-option jscreen tcp port-scan threshold 1000
set tenants TN1 security screen ids-option jscreen tcp syn-ack-ack-proxy threshold 500
set tenants TN1 security screen ids-option jscreen tcp syn-flood alarm-threshold 500
set tenants TN1 security screen ids-option jscreen tcp syn-flood attack-threshold 500
set tenants TN1 security screen ids-option jscreen tcp syn-flood source-threshold 50
set tenants TN1 security screen ids-option jscreen tcp syn-flood destination-threshold 1000
set tenants TN1 security screen ids-option jscreen tcp syn-flood timeout 10
set tenants TN1 security screen ids-option jscreen tcp land
set tenants TN1 security screen ids-option jscreen tcp winnuke
set tenants TN1 security screen ids-option jscreen tcp tcp-sweep threshold 1000
set tenants TN1 security screen ids-option jscreen udp flood threshold 500
set tenants TN1 security screen ids-option jscreen udp udp-sweep threshold 1000
set tenants TN1 security zones security-zone untrust screen jscreen
Step-by-Step Procedure

The following example requires you to navigate various levels in the configuration hierarchy. For instructions on how to do that, see Using the CLI Editor in Configuration Mode in the Junos OS CLI User Guide.

To configure destination-based session limits in a tenant system:

  1. Log in to the tenant system as the administrator and enter configuration mode.

    content_copy zoom_out_map
    user@host:TN1#> configure
    user@host:TN1# 
    
  2. Define the tenant system name as TN1 and configure a screen option for a destination-based session limit.

    content_copy zoom_out_map
    [edit tenants TN1]
    user@host:TN1# set security screen ids-option jscreen limit-session destination-ip-based 80
    
  3. Configure the ICMP screening options.

    content_copy zoom_out_map
    [edit tenants TN1 security screen ids-option jscreen]
    user@host:TN1# set icmp ip-sweep threshold 1000
    user@host:TN1# set icmp fragment
    user@host:TN1# set icmp large
    user@host:TN1# set icmp flood threshold 200
    user@host:TN1# set icmp ping-death
    
  4. Configure the IP screening options.

    content_copy zoom_out_map
    [edit tenants TN1 security screen ids-option jscreen]
    user@host:TN1# set ip bad-option
    user@host:TN1# set ip stream-option
    user@host:TN1# set ip spoofing
    user@host:TN1# set ip strict-source-route-option
    user@host:TN1# set ip unknown-protocol
    user@host:TN1# set ip tear-drop
    
  5. Configure the TCP screening options.

    content_copy zoom_out_map
    [edit tenants TN1 security screen ids-option jscreen]
    user@host:TN1# set tcp syn-fin
    user@host:TN1# set tcp tcp-no-flag
    user@host:TN1# set tcp syn-frag
    user@host:TN1# set tcp port-scan threshold 1000
    user@host:TN1# set tcp syn-ack-ack-proxy threshold 500
    user@host:TN1# set tcp syn-flood alarm-threshold 500
    user@host:TN1# set tcp syn-flood attack-threshold 500
    user@host:TN1# set tcp syn-flood source-threshold 50
    user@host:TN1# set tcp syn-flood destination-threshold 1000
    user@host:TN1# set tcp syn-flood timeout 10
    user@host:TN1# set tcp land
    user@host:TN1# set tcp winnuke
    user@host:TN1# set tcp tcp-sweep threshold 1000
    
  6. Configure the UDP screening options.

    content_copy zoom_out_map
    [edit tenants TN1 security screen ids-option jscreen]
    user@host:TN1# set udp flood threshold 500
    user@host:TN1# set udp udp-sweep threshold 1000
    
  7. Attach the IDS profile to the zone.

    content_copy zoom_out_map
    [edit tenants TN1]
    user@host:TN1# set security zones security-zone untrust screen jscreen
    
Results

From configuration mode, confirm your configuration by entering the show tenants TN1 security screen command. If the output does not display the intended configuration, repeat the configuration instructions in this example to correct it.

content_copy zoom_out_map
user@host# show tenants TN1 security screen
ids-option jscreen {
    limit-session {
        destination-ip-based 80;
    }
}
ids-option jscreen {
    icmp {
        ip-sweep threshold 1000;
        fragment;
        large;
        flood threshold 200;
        ping-death;
    }
    ip {
        bad-option;
        stream-option;
        spoofing;
        strict-source-route-option;
        unknown-protocol;
        tear-drop;
    }
    tcp {
        syn-fin;
        tcp-no-flag;
        syn-frag;
        port-scan threshold 1000;
        syn-ack-ack-proxy threshold 500;
        syn-flood {
            alarm-threshold 500;
            destination-threshold 1000;
            timeout 10;
        }
        land;
        winnuke;
        tcp-sweep threshold 1000;
    }
    udp {
        flood {
            threshold 500;
        }
        udp-sweep threshold 1000;
    }
}

Verification

To confirm that the configuration is working properly, perform the below task:

Verifying security screen status

Purpose

Verify that the IDS profile for multiple screening options is configured properly:

Action

To verify the configuration is working properly, enter the show security screen ids-option jscreen tenant TN1 and show security zone tenant TN1command from operational mode.

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user@host> show security screen ids-option jscreen tenant TN1 

  Screen object status:

  Name                                       Value
  ICMP flood threshold                       200
  UDP flood threshold                        500
  TCP winnuke                                enabled
  TCP port scan threshold                    1000
  ICMP address sweep threshold               1000
  TCP sweep threshold                        1000
  UDP sweep threshold                        1000
  IP tear drop                               enabled
  TCP SYN flood attack threshold             500
  TCP SYN flood alarm threshold              500
  TCP SYN flood source threshold             50
  TCP SYN flood destination threshold        1000
  TCP SYN flood timeout                      10
  IP spoofing                                enabled
  ICMP ping of death                         enabled
  TCP land attack                            enabled
  TCP SYN fragment                           enabled
  TCP no flag                                enabled
  IP unknown protocol                        enabled
  IP bad options                             enabled
  IP strict source route option              enabled
  IP stream option                           enabled
  ICMP fragmentation                         enabled
  ICMP large packet                          enabled
  TCP SYN FIN                                enabled
  TCP SYN-ACK-ACK proxy threshold            500
content_copy zoom_out_map
user@host> show security zone tenant TN1 

Security zone: untrust
Send reset for non-SYN session TCP packets: Off
Policy configurable: Yes  
Screen: jscreen   
Interfaces bound: 0
Interfaces:
Meaning

The output displays the screen status in the tenant system.

Change History Table

Feature support is determined by the platform and release you are using. Use Feature Explorer to determine if a feature is supported on your platform.

Release
Description
18.3R1
Starting in Junos OS Release 18.3R1, the screen options that are supported for logical systems are extended to tenant systems.
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