Email spoofing is on the rise. Country IP Blocks estimates that spoofing may account for more than 80% of all spam and malicious email traffic. Email spoofing is defined as the forgery of an email header so that the message has the appearance of originating from a source other than the actual source.
While any spoofed email is a problem, the problem becomes magnified when the spoofed email appears to come from an expected source. For example, company EXAMPLE has 100 employees and each employee has an EXAMPLE email account. If the company is using a program like SpamAssassin or other similar anti-spam software, they probably use a blacklist and whitelist to aid the spam filters. Company EXAMPLE may use a wildcard to blacklist *@EXAMPLE.com and then whitelist their legitimate email accounts, such as john_doe@EXAMPLE.com. The spam filters will give special consideration to email accounts appearing on the whitelist. Here is where a major problem may begin. Read more…
Server Log files are your friend. Depending on your server and server settings your system produces a variety of log files. These may include access, error, SSL, ftp and other logs. Use them to glean important marketing, error correction and security information for your server and/or websites. But some administrators may not have access to their server’ logs or they may want to create specific logs that are easily accessible and provide on the fly information. In this tutorial we will teach you how to create your own security logs. Read more…
In this lesson we will attempt to simplify the identification of the Network and Broadcast address using a known IP address, within the network or subnet, and the CIDR or Netmask. In this lesson we will walk you through the terms you need to know, the basic math and some examples.
Terms you need to know: Read more…
All network professionals need to have a firm grasp of the principles behind IP addressing. This includes understanding how an IP address is associated with a specific network. This is done by using a network address and CIDR to calculate the Network Address, Network Range and Broadcast Address. But the first place we need to start is with a simple understanding of an IP address and it’s conversion to binary and decimal. Read more…