Postgrey and the power of Greylisting to fight Spam

Sunday, March 13th, 2011

Wow…. Let me just say that I have typically been inundated with junk mail on my primary address. It’s associated with this domain and has been hosted in an older sendmail setup for quite some time (not really by choice, but because that’s what was installed on the old vps.) I’m currently migrating to postfix [...]

Mail Server Rejecting all Messages – Check your Blacklists relays.ordb.org is listing the WORLD

Monday, March 31st, 2008

It’s unusual for mail servers to suddenly start rejecting messages internally and from external sources. That’s exactly what I saw though over the weekend. A mailserver running mdaemon on Windows 2000 was rejected ALMOST every message that was sent it’s way whether it was an internal mail sender and recipient or external sender to internal [...]

Why? (Why couldn’t AT&T make sure their mail servers weren’t using old dialup IPs that are blacklisted….)

Tuesday, July 24th, 2007

Why do I always wind up being the one to discover problems? …. Today in checking mail I found a mail that had bounced back from one of my clients that uses bellsouth… Now bellsouth has recently been bought by AT&T and it appeared as though the mail had been rejected because the mailserver trying [...]

Symantec Antivirus Remotely Exploitable Vulnerability

Friday, May 26th, 2006

This is bad – whose defending the defender? eEye security has a bulletin announced that regards a remotely exploitable vulnerability in Symantec Antivirus 10.x and Symantec Client Security 3.x They say other versions MAY be vulnerable they’re waiting for information from Symantec. Now, Symantec is probably the biggest selling antivirus package out there. It looks [...]

Evolution email error MAIL FROM command failed: Unknown

Thursday, March 30th, 2006

Some time back, I was teetering on the brink…. I’ve used Evolution as my linux mail client for ages (since I switched), because it had the calender integrated etc… However, Kontact has REALLY looked nice for some time, but I didn’t have time to mess with changing. Then one day, I was trying to send [...]

Network security – what does arp spoofing mean for wireless?

Monday, January 30th, 2006

So, if you haven’t already had enough cause to tighten your wireless security…. we’ve been talking about arp poisoning (spoofing) and the basic conclusion is that IF an attacking machine is on the same subnet as your machine (same IP address range), they can “own” all traffic from you machine to the gateway. It doesn’t [...]

Bellsouth mail.lig.bellsouth.net server phasing out?

Wednesday, January 18th, 2006

I haven’t had much time to look into this, but one of the mailservers I administer is typically configured to relay through mail.lig.bellsouth.net, with mail.averyjparker.com as a fallback. Sometime overnight, mail.averyjparker.com started getting heavy use and on checking this morning was getting all of the outbound traffic. So, I did a bit of investigation mail.lig.bellsouth.net [...]

Network Security guide for the home or small business network – Part 3 – Antivirus

Thursday, December 15th, 2005

Ok, the first two entries thus far, hardware firewalls and software firewalls have been fairly operating system independant. A hardware firewall is best, but if that’s not possible a software firewall will do until you get a hardware firewall setup. This next item is (currently) a must have for Windows users. However, Mac and Linux [...]

New Sober variants..

Tuesday, November 22nd, 2005

Ok – there are some new variants on the Sober worm circulating. I received one on an address that’s unfiltered (no virus/spam filtering) and must say, I can see people being duped into looking at the attachment. Sans has a post on it.. Sarc is calling it W32sober.x@mm and rates it at a threat level [...]

Ways to deal with Junk Mail (2 of 2)

Sunday, August 7th, 2005

Okay, in a previous post I talked about a server side solution for junk mail filtering. Now it’s time to ask…. “what if I can’t install filtering software on our mailserver?” Here is one way to deal with the answer…    Send article as PDF   

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