Unfortunately spamhole’s day is mostly behind us though I wish I would have been familiar with it earlier. The spamhole application developers took the approach of developing spamhole for other like minded individuals to assist in battling the SPAM issues on the Internet by creating fake open mail relays as possible and thus tricking spammers into sending their SPAM into blackholes or honeypots. It would have been extremely satisfying to watch SPAM enter a spamhole fake open relay I had created and be redirected to nothing. The spamhole application is not working as of Backtrack 5 R3 and is explained in more detail below.
I have been wanting to get the use of dig on Windows 7 for awhile but hadn’t taken the time to do so until now. The problem is nslookup is not as helpful in terms of TTL of zone files, etc. and while you can accomplish your tasks with nslookup using dig makes life much easier on Windows 7 when troubleshooting DNS type issues. The other night I was in the middle of a time critical launch of a new web cluster and needed dig on the Windows 7 laptop I was working on so I decided to get it working while I was waiting for some data to transfer. I actually had slipped on setting the TTL, which was for a single sub domain that was part of the transfer, from a TTL of a entire day (86400 seconds) to a TTL of one hour (3600 seconds). Anyhow below is more information on installing dig on a Windows 7 computer.
Yesterday I wrote an article about securing your /tmp and /var/tmp directories on a Linux server because I had found some files uploaded to the /tmp directory via the apache user. After locking down those directories I wanted to verify that there were no other issues on the server so I installed Rootkit Hunter and Rootcheck which are two applications that will assist you with verifying the integrity of your Linux server. Below is information on installing Rootkit Hunter and Rootcheck as well as information on how to use each of them effectively.
Yesterday a colleague at my company was doing some testing with a potential partner and they needed to open a TCP port on one of our development servers so an application could bind to that port. At first I wasn’t sure how I should do this since the port didn’t need to do anything but listen for incoming connections and the remote application would simply connect to that port. To get something up immediately for them I simply had our web server listen on the requested port which worked however I did not want the web server running on this port for long so I needed to come up with another solution to simply open the port, listen for connections, and possibly log those connections so we could troubleshoot if necessary. I ended up finding an application called tcpsnoop which I explain how to compile and use below.
Installing dig on a CentOS Linux server is easy with yum. Dig is actually a bind tool so you will be required to install some bind libraries along with the bind utility package.
- [root@server ~]# yum install bind-utils
Now you can run something like the below using dig to find MX records.