Category Archives: Linux

Discoveries and adventures in Linux, computers, and networking

Network Booting with DNSMASQ in Proxy Mode

In this project, I will show you how to network boot an Arch Linux ISO image with DNSMASQ set up in proxy DHCP mode. The approach taken here should readily generalize to the ISO images of other distributions. If you understand what’s being done here, adapting to another distribution should not be too difficult. I’m indebted to the Arch Linux… Read More »

Amazon Web Services S3 via Command Line

Amazon Web Services (AWS) has a nice Command Line Interface, allowing script or command line access to quite a wide range of capabilities. I recently attempted to use this with the Simple Storage Service (S3), but was frustrated with a repeated error message in response to a simple directory request on a bucket. jeff@mars:~$aws s3 ls s3://MyBucket A… Read More »

Fixing VSFTPD login problem

I recently set up a new Ubuntu 12.04 server, and as part of the setup installed vsftp. I used an identical setup to a similar server, but for some reason, I kept getting an authentication error attempting to login as a local user. After a lot of troubleshooting, I finally isolated the problem to the PAM script for… Read More »

Faster IPSET loading

IPSETs are a very efficient way to manage a large list of IP addresses for your iptables firewall. Rather than have an individual rule for each and every address or network that needs to be dropped or rejected, with ipsets you can have a single iptables rule that tests an entire list of addresses. The rule would look something… Read More »

Botnet Attack

As has been extensively publicized elsewhere, a very large scale botnet has been organized to attack sites using WordPress. This site has the dubious honor to have been included this last weekend. The attack attempts to log in to the site using the user name “admin” or a number of variants on that name, then uses a dictionary… Read More »