IT Security & Network Engineering Knowledge Base

Practical documentation and technical guides on network security, firewalls, Linux systems, monitoring, and automation.
We feature technical articles across the entire IT spectrum - Built from real-world experience and continuously updated.

Juniper SRX Commands

Below shows some of the main Juniper SRX commands available. All commands are provided with the necessary mode in which they should be run from. Configuration Commands replace pattern expr1 with expr # configuration mode find and replace string within configuration show | compare rollback {1..5} # configuration mode compare the current configuration against roll … Read more

F5 LTM VE 10.2.x – Interfaces not recognised

When running the BIG-IP LTM (10.2.3) virtual appliance on ESX4 you may observe that only the management interface is seen by the system. [root@localhost:Active] config # b interface showINTERFACEKey     Speed    Pkts Pkts Drop Coll   Bits   Bits Errs Trunk         Mbps      in  out               in    outmgmt UP   100 FD  511    8    0    0 266144   5056    0 Solution To … Read more

Cisco ASA – Security Levels / NAT Control

Within the Cisco Firewall family (PIX/ASA) there are 2 security features known as Security Levels and NAT Control. Security Levels Security levels are numeric values (between 0 and 100) which are assigned to the firewalls interfaces and used to control traffic flows. Traffic is allowed to pass from a higher security level to a lower … Read more

F5 LTM – OneConnect

Overview The OneConnect feature works with HTTP Keep-Alives to minimize the number of server-side TCP connections by reusing existing connections for further HTTP requests.“OneConnect” has 2 methods. They are : OneConnect Profile and OneConnect transformations. Both of which are explained within this article. HTTP Requests Overview HTTP/1.1 requests – HTTP/1.1 dictates that HTTP Keep-Alive connections … Read more

Django – CSRF verification failed. Request aborted.

Issue When trying to access your Django site within CSRF configured you receive the following via a Forbidden (403) HTTP error message: CSRF verification failed. Request aborted.No CSRF or session cookie. Solution In my scenario I found that the order of settings.MIDDLEWARE_CLASSES was incorrect. Below shows you an example settings.py MIDDLEWARE_CLASSES = (    ‘django.middleware.csrf.CsrfViewMiddleware’,    ‘django.middleware.common.CommonMiddleware’,    … Read more

F5 LTM – Connection Management

Adaptive Reapers Adaptive reapers provide the ability for the system to automatically clear connections at the point of a predefined threshold being reached. This provides both system and connection stability during the point of a Denial of Service attack.At the point memory usage reaches the low water mark threshold (default %85) all half open connections … Read more

F5 LTM VE – Unable to attach to PCI device 02:01.00 for Interface 1.1

When running the BIG-IP LTM (10.1) Virtual appliance on ESX4 you may observe the following error message (within the /var/log/message file): Unable to attach to PCI device 02:02.00 for Interface 1.1 This results in both interfaces forming the status of un-initialized and in turn failing to pass traffic. Solution To resolve this define each interface … Read more

Brocade ADX – FTP

The Brocade ADX offers 2 methods in which to configure FTP SLB (Server Load Balancing). These methods are : Layer 3 – Uses the sticky and concurrent connection settings to provide FTP SLB.Layer 4-7 – Provides FTP SLB via the use of FTP application awareness (introduced in version 12.3.1d). 1. Layer 3 To Load-balance either … Read more

PKI – Chain of Trust

Purpose  The main purpose of this document is to explain the PKI term ‘Chain of Trust’. Summary PKI (Public Key Infrastructure) is a framework built upon protocols, services and standards used to provide authentication, confidentiality, integrity, non-reproduction and access control to digital data. The term ‘Chain of Trust’ is used to describe the trust relationship … Read more