Juniper SRX – Dynamic VPN

Within this tutorial we will be showing you how to configure Remote Access VPN (Dynamic VPN) on the Juniper SRX. IKE Configure Aggressive Mode set security ike policy ike-dyn-vpn-policy mode aggressive set security ike policy ike-dyn-vpn-policy proposal-set standard Define Preshared Key set security ike policy ike-dyn-vpn-policy pre-shared-key ascii-text <PRE-SHARED KEY> Configure the IKE Gateway Here … Read more

Juniper SRX – How to configure a policy based VPN

Below shows the necessary steps/commands to create a policy based VPN on a Juniper SRX series gateway. The main difference with a policy based VPN is that the tunnel action is defined within each security policy. Note : For troubleshooting steps please see here This VPN is configured with the following : Remote Endpoint : … Read more

How do I upgrade a Juniper SRX Series gateway

Within this tutorial we will be providing the steps required to upgrade your Juniper SRX firewall. Copy Image First of all we copy the image over to the SRX via the use of scp. In this case I have used putty’s pscp. C:\Windows\System32>pscp “C:\Users\admin\Downloads\junos-srxsme-11.4R1.6-domestic.tgz” root@[SRX IP]:/mfs Confirm Hash Next we confirm that the file is … Read more

Cisco ASA – How do I capture ARP`s ?

Below shows the necessary commands to capture ARP packets on a Cisco ASA Firewall. Syntax ASA(config)# capture arp ethernet-type arp interface dmz  Display ASA(config)# show capture arp2 packets captured 13:12:23.478229 arp who-has 10.1.1.1 tell 10.1.1.10013:12:26.784194 arp who-has 10.1.1.1 tell 10.1.1.1002 packets shown

Juniper SRX – Configuring Source NAT with pool

Below provides a short guide in configuring source NAT with an address pool on a Juniper SRX. The following example creates a pool with a 10.1.1.0/24 network. This pool of addresses are then used during the translation of source addresses. In addition to the pool we also configure the following options: set address-persistent – this … Read more

Running a packet capture on a Juniper SRX

Within this article we show you the required steps for obtaining a packet capture on your SRX series firewall. Note : Great care should be taken when applying captures to ensure that only the traffic that you want to capture is defined within the firewall filter. This is to prevent any unnecessary load being placed … Read more

How to define a port range on a Juniper SRX

To create a range of ports within the SRX the following command is used. This example creates an application object named UDP-PORT-RANGE with a UDP port range of 5000-6999. set applications application UDP-PORT-RANGE protocol udp destination-port 5000-6999 Once created you can then add this to a group. This group can then be added to the necessary … Read more

Mitigating DoS attacks on a Cisco ASA

Within this example we will configure modular policy framework to define a range of connection limits. This provides a basic means of protecting your environment against DoS attacks. Define Traffic First of all we define which traffic the MPF policy will be applied to. In the example below we exclude the host 8.8.8.8 whilst inspecting … Read more

How do I clear the Cisco ASA connection counters ?

Being that this command is slightly obscure I thought it was worth documenting. To clear the Cisco ASA connection counter the following command is used. cisco-asa(config)# clear resource usage resource conns

Cisco ASA: Traffic blocked when TCP syslog server is unreachable

Issue When the transport mechnism TCP is configured for Syslog (trap logging) and the Cisco ASA is unable to reach the designated syslog server, the security appliance will prevent any further new network sessions. Solution In order to ensure that the status of a TCP-based syslog server is irrelevant to new sessions the following command … Read more

Troubleshooting a Site to Site VPN on a SRX Series Gateway

Within this article we will look at the various steps required in debugging a Site to Site VPN on an SRX series gateway. 1. Confirm Configuration First of all check the VPN configuration. This is also useful if and when you need to confirm the Phase 1 and Phase 2 parameter’s with the remote end. … Read more

Juniper SRX – Configuring PPPoE

Within this article the necessary steps required to configure PPPoE on the SRX platform are described. Note : This configuration is based upon a) the chap authentication method b) the outside/untrust interface being fe-0/0/7.0. Configuration Below shows the required configuration for PPPoE. set interfaces fe-0/0/7 unit 0 encapsulation ppp-over-ether set interfaces pp0 unit 0 ppp-options … Read more

Juniper SRX – DynDNS

As it stands Juniper SRX (version 11.1R1.10) only provides support for DynDNS (DDNS) via the use of an automation script. Configuration This script can be downloaded here. Once you have downloaded the script transfer it to the SRX directory /var/db/scripts/event/. Finally configure your SRX via the following commands : set system services apply-macro dyndns-client1 hostname XXX.dyndns.orgset … Read more

SRX Dynamic VPN – No proposal chosen (14)

Issue When connecting trying to connect via Dynamic VPN your client displays the following error:         IKE Negotiations Failed Within the output of the IKE debug logs you see the following error: Jul 26 11:35:46 ike_st_i_n: Start, doi = 1, protocol = 1, code = No proposal chosen (14), spi[0..0] = 00000000 00000000 …, data[0..0] … Read more

Configure Global Explicit Deny on a SRX Series Gateway

To configure a global deny statement for all your policy entries the following commands are used. set groups global-policy security policies from-zone <*> to-zone <*> policy default-logdrop match source-address any set groups global-policy security policies from-zone <*> to-zone <*> policy default-logdrop match destination-address any set groups global-policy security policies from-zone <*> to-zone <*> policy default-logdrop … Read more

How do I enable Global Logging on a Juniper SRX ?

Below details the nessecary commands required to enable global logging on all security policies. set groups global-logging security policies from-zone <*> to-zone <*> policy <*> then log session-initset security policies apply-groups global-logging

How do I configure PMTU on a Juniper SRX series gateway ?

By default IPv4 Path MTU is enabled. However all PMTU options can be located under [set system internet-options ….]. root@srx100# set system internet-options ?Possible completions:+ apply-groups         Groups from which to inherit configuration data+ apply-groups-except  Don’t inherit configuration data from these groups  gre-path-mtu-discovery  Enable path MTU discovery for GRE tunnels> icmpv4-rate-limit    Rate-limiting parameters for ICMPv4 messages> … Read more

Juniper SRX – Securing Management Access

Within this article we will show the required commands to restrict and secure management access to your Juniper SRX series gateway. Note : The following syntax/configuration has been tested with a PPPoE setup. Configure Addresses First of all the addresses that are allowed management access to the device are configured. This also includes any DNS … Read more

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