logins

How to access iPhones remotely using OpenSSH

A jail broken Apple iPhone with OpenSSH installed is accessible over the internet using ssh and the default root password “alpine“. You can use a short script to find IP addresses that have port 22 open and try to login. You can run this script from your Mac or any Linux machine. #!/bin/shfourth=1 third=0 mkdir [...]

How to access your server via SSH

If you are unfamiliar with SSH this is ok. This is a simple explanation to get you to a command prompt on your new server or existing server. Simply download a program called “putty.exe” if you are using Windows. If you are using MAC you will need to jump in to the shell and follow [...]

How to configure to allow Interfaces in IPtables

You would like to block all network traffic using iptables firewall under Debian GNU/Linux. This will block all incoming and outgoing traffic including Internet aka ADSL/ppp0 and it is highly recommend. The logic is block everything and allow only required traffic. This can be done with four simple commands: # iptable -F # iptables -P [...]

How to Verify Email Security With tcpdump

I can use tcpdump to verify that encryption is working. Here is what a plain unencrypted POP mail session looks like. This is an abbreviated example showing only the initial three-way TCP handshake. You can do this yourself by firing up tcpdump, then checking mail. Ctrl+C stops it: # tcpdump port 110 15:04:49.050227 windbag.34348 > [...]

How to configure xinetd package in fedora

 xinetd, the eXtended InterNET Daemon, is an open-source daemon which runs on many Linux and Unix systems and manages Internet-based connectivity. It offers a more secure extension to or version of inetd, the Internet daemon. xinetd performs the same function as inetd: it starts programs that provide Internet services. Instead of having such servers started [...]

Essential Linux Server Administrator Commands

Command Summary Use arp Command mostly used for checking existing Ethernet connectivity and IP address Most common use: arp This command should be used in conjunction with the ifconfig and route commands. It is mostly useful for me to check a network card and get the IP address quick. Obviously there are many more parameters, [...]

How to configureiptables to allow only specific hosts to connect to ssh service

An alternative to TCP wrappers (although you can use both at the same time) is limiting SSH access with iptables. Here’s a simple example of how you can allow only a specific host to connect to your SSH service: ~# iptables -A INPUT -p tcp -m state –state NEW –source 193.180.177.13 –dport 22 -j ACCEPT [...]

How to Use TCP wrappers to allow only specific hosts to connect to ssh Service

This approach is useful if you would like to allow only specific hosts on a network to be able to connect to your SSH service, but you don’t want to use or mess up your iptables configuration. Instead, you can use TCP wrappers; in this case the sshd TCP wrapper. I will make a rule [...]

How to Build a diskette-based bandwidth management system – PicoBSD

Many users, despite having a good Net connection, complain about poor surfing and download speeds. While an organization could pay for additional bandwidth, a better option might be to manage the bandwidth they already have. There are numerous bandwidth management software tools available. In this article we will explore managing network bandwidth using the dummynet [...]

How to Use User Accounting to discover information on Linux Box

User accounting can be used to discover information about who is currently using the system. While you cannot necessarily verify the integrity of this information once your machine has been exploited, it can be a useful tool to track the systems a particular user has logged into, what time he or she logged in, when [...]