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OSX Built-in TFTP Server

OSX has a built-in TFTP server, but starting it the OSX way may not be 100% obvious to you. sudo launchctl load -F /System/Library/LaunchDaemons/tftp.plist sudo launchctl start com.

HA Recursive DNS with dnsdist and exabgp

I’ve wanted to use exabgp along with dnsdist to provide anycasted, highly available recursive DNS servers ever since discovering dnsdist. This is a fourth in blog series about DNS, specifically awesome things that can be done with dnsdist.


I’ve often wished for a way of logging pings when troubleshooting connectivity problems. Today I revisited the problem using fping. fping and fping6 both have options to run a continuous ping (-l), and when combined with -D to insert the unix timestamp, can log the latency and loss to a destination in 1s increments.

Mikrotik, VRRP, and IPv6

I recently setup IPv6 first-hop redundancy in my colocated environment using Mikrotik and VRRP. It didn’t work the same way I’d come to expect from using it in IPv4 environments and I set out to figure out why.


DDoS attacks continue to be a wide-spread problem on the internet. Their size has grown over the past few years to where BGP Blackholing to reduce collateral damage has become widespread.

HA Authoritative DNS w/ dnsdist

I ran into an obscure limitation in PowerDNS 4.0 authoritative server recently. I have one nameserver which also acts as a slave to two other sets of zones with are transfered using AXFR.