If you have domains that do not send emails, you still need to lock them down so no spammers can spoof these domains to send emails. All you need is to add the following two DNS records to your domain’s DNS. First, a block-all SPF txt record: v=spf1 -all And a DMARC policy that rejects all email that fails SPF. […]
I have a Ubuntu VPS that runs a bunch of websites powered by MySQL server at the back end. For whatever reason, the websites just kept turning down because of the crush of the MySQL service. I could scale up the server to dip in more memory or set up some sort of monitoring system to monitor and restart MySQL […]
This is a very nicely written cheat sheet by JDow.io for web application penetration testing. This cheat sheet is intended to run down the typical steps performed when conducting a web application penetration test. I will break these steps down into sub-tasks and describe the tools I recommend using at each level. Many of the ideas presented in this sheet […]
This iSCSI based SAN has been serving me extraordinarily well for 7 years and one of the controllers in the machine decided to give out the other day. So I was down to one controller serving a bunch of VMs and I needed to replace the defective one so it can be running in full redundant mode again. Purchasing the […]
First of all, here is why RAID 5 is so bad and has stopped working since 2009. To recap, two things to blame here. UREs (Unrecoverable Read Error) Disk storage capacity Here is an example to illustrate why it’s so bad having RAID 5 on large capacity hard drives. With a 7-2TB drives RAID 5 setup, when one drive failed, you […]
The network stack does several seemingly impossible things. It does reliable transmission over our unreliable networks, usually without any detectable hiccups. It adapts smoothly to network congestion. It provides addressing to billions of active nodes. It routes packets around damaged network infrastructure, reassembling them in the correct order on the other side even if they arrived out of order. It […]
A bit IT disaster hit British Airways past weekend and caused misery for tens of thousands of customers of the airline. Here are some of the resources collected by the guy that runs WServerNews newsletter. Quite a long list of materials to read: To begin with here are a few background news articles which may or not be relevant to […]
Compiled by Aaron W from Spiceworks, here are 13 free network monitoring tools that will help you detect when your network is down — and hopefully help you prevent it from going down in the first place. Microsoft Network Monitor Nagios OpenNMS Spiceworks Network Monitor Spiceworks Connectivity Dashboard PRTG Network Monitor The Dude Zabbix Zenoss Core Icinga Pandora FMS WireShark Observium […]