As systems administrators, we abhor spam. It bogs down servers, floods our personal mailboxes, and wastes our user’s time. As web content providers, we also are extremely annoyed that email contact information is blatently reaped and abused. The Internet can be so much more than a cesspool of spam. On the other hand, the Internet […]
Cloudmark SpamNet
Landmark Washington Spam Case Victory
As you may or may not know, Washington State has a spam law that forbids deceptive email practices. For more info on this law see this area of the Attorney General of Washington’s website. Well, a landmark case regarding this law has just been decided. We put a copy of the release up on NetAdminTools […]
Test SMTP (email) via Telnet
One good trick to use when testing your email server is to use telnet. To send email, you can just telnet into the destination email server directly: u-1@srv-1 u-1 $ telnet yourmailserver.com 25 Trying 21.40.23.46… Connected to yourmailserver.com. Escape character is ‘^]’. 220 mx.yourmailserver.com ESMTP Sendmail 8.12.9/8.12.9; Thu, 12 Jun 2003 10:06:19 -0700 helo frommail.com […]
Osirusoft Is Blocking All Hosts
Due to DDoS attacks on Osirusoft, Osirusoft decided to reject all. So, if you are using Osirusoft to block spam, stop! Well, hats off to the valiant efforts of Osirusoft. Can’t really blame them for their reaction to this world of shit. The beautiful thing is that sysadmins and others in our community will find […]
Using Watch-maillog To Reduce Spam Chatter
It is truly amazing how many resources are taken up on a server by other rogue boxes searching for an open relay, or simply sending dictionary attempts at finding local users. Watch-maillog is a perl script that uses IPtables to block mail servers that abuse your server. Watch-maillog helps with this by blocking servers that […]
Setting Reply-to Address in Pine
We often need to mail brief messages from servers to send config files, or quick messages to other sysadmins. Pine works well for this, and the installation is mostly a single binary. We usually are logged in on some account that isn’t the email address we wish replies to come to. It turns out that […]
Adding an Alias to Postfix
If you simply want to make a mailbox receive mail for another address, just add the full address to /etc/postfix/virtual: [root@srv-2 postfix]# cat virtual usr-1@networking.com usr usr-1@networking2.com usr usr-2@maildomain.com anotherusr If we simply add this line to the bottom: usr-3@maildomain.com anotherusr Mail that was was delivered previously via usr-2@maildomain.com will be delivered in the same […]
Wadding up Spambots With Spiderkiller
Spiderkiller is a C program that will generate unique pages with random email addresses that will confuse harvesting bots. Compile the app: srv-5:~ usr4$ gcc spiderkiller.c -o spiderkiller spiderkiller.c: In function ‘main’: spiderkiller.c:299: warning: incompatible implicit declaration of built-in function ‘strlen’ The options are simple: srv-5:~ usr4$ ./spiderkiller -help Usage: spiderkiller [-help] [-n ] [-k […]
Postfix RPM Upgrade for Red Hat Enterprise Linux 3
One of the servers we work on is running Red Hat Enterprise Linux 3 (RHEL 3). We needed some features in the later versions of Postfix, rather than the backported version for RHEL 3. There are some RPMs available here: http://postfix.wl0.org/ftp/official/2.2/RPMS-rhel3-i386 The latest version as of the date of this article is 2.2.5-3. If you […]
Postfix Source RPM Upgrade for Red Hat Enterprise Linux 3
In this article, we upgraded Postfix to 2.2.5 via RPMs; however, if a later version is needed, and you are running Red Hat Enterprise Linux Version 3 (RHEL 3), an RPM needs to be created from source. There is a source RPM for 2.2.6 available here: http://postfix.wl0.org/ftp/official/2.2/SRPMS/ To use the RPM, install it: [root@s root]# […]
Using UW IMAP and Xinetd For Dual SSL and Plaintext Support
First off, Pine rocks when it comes to reading mail quickly, particularly on a server where a GUI is not available. Second of all, it often doesn’t come with GNU/Linux distributions anymore. I suppose that part of the problem is that pine includes a version of IMAP that can cause problems if it coexists with […]
Avoid Unwanted Email
The opportunists who send unsolicited bulk email (UBE) use tools that do not follow standards. This can work to an advantage in that improper configuration can allow quite a bit of filtering to be done on inbound email. For instance, the following entries in main.cf for postfix will dramatically cut down on email from misconfigured […]
The Network Administrator (.com)
Check out TheNetworkAdministrator for some good reads. We have some strange stuff on NetAdminTools, but a full tab just called Conspiracy Theory. Very enjoyable. Visit the site and realize that you aren’t the only Monkey Life-Partner out there.
Transform dot com Schwag Into Something Useful
I have a cap from hardware.com. [I actually turned down a job offer from these folks in the fall of ’99. They only lasted a year or so after that. They intended to be a place where people could order tools, wheelbarrows, etc. on the Internet.] I also like to read at night. I happen […]
Virtualization Between the Platform and the Application With Java
What if Java is it. Java has virtualized the world between the platform and the application to the point, really, that all of the knowledge you are building to run the OS of your server is becoming somewhat trivial. True, you can install a new version of glibc, and know how to solve dependencies with […]
Click-Free Web App And Mouse Movement Fingerprinting
Check out DONTCLICK.IT for a very cool concept site that shows an example of navigation without mouse clicks. One interesting implication is the biometric fingerprinting possibilities. One area of the site allows you to see the movements of previous visitors to the site. It seems possible to us that tracking the movements of a mouse, […]
HP and the Business Domain
I was thinking about HP and their decision to get out of the PC market and purchase Autonomy. It makes sense to me. HP can do well in the business information domain. Domain… information… There are three main domains for information: personal, business, and public. The Internet was primarily used as public after the burst […]
Using DJGPP and other UNIX-like tools to manage NT servers
What is it? DJGPP is a collection of UNIX-like tools for DOS/Windows that has been ported from the GNU project. For a better understanding of what we mean by UNIX-like, see gnu.org. We’ve found DJGPP indespensible for tweaking files for automated installs from the command prompt. With this version you can run the utilities from […]
Compiling Opensource programs on NT/95/98
Windows users are at a disadvantage in the open source environment becase they are not used to compiling programs. The idea of recompiling the NT kernel just simply doesn’t cross the mind of a typical MCSE. Programs are usually shipped precompiled. In the *nix world it is routine to download the source code for a […]
Creating an NT Server Test Lab Using VMware
One thing we do quite often here at netadmintools.com is install and reinstall NT Server and friends over and over again. This article describes how to setup, configure, backup to tape, and restore an NT Server installation on Vmware. We installed Vmware using the simple directions that came with the distribution, and then ran a […]
