hardcoded DNS will bite you in the ass in the most subtle and annoying ways

tl;dr - make a list of all of the annoying places where you need to hardcode DNS entries. you’ll thank yourself later. i retired a DNS server this past week. couple that with the expiration of a couple of guest wifi passes and i discovered that there’s a hidden DNS setting on the APs that can make captive portal DNS resolution miserable if the DNS server is offline. on ubiquit APs the preferred DNS server in the AP is what’s used for the resolution of DNS for the hotspots....

December 25, 2019 · 1 min · sulrich

foo-lab topology building

overview to build a virtualized network topology from the most base elements it’s as simple as starting a virtual machine with the necessary number of virtualized interfaces and interconnecting these virtual interfaces to other virtual machines or physical interfaces. while there are tools1 which will nicely automate the creation of topologies and handle the lifecycle of VMs. all of these are effectively placing a nice wrapper around the following process....

May 20, 2019 · 6 min · sulrich

gossip protocol

application layer multicast from stuff the internet say on scalability … ...

February 7, 2016 · 1 min · steve ulrich

software dataplane verification

abstract The industry is in the mood for programmable networks, where an operator can dynamically deploy network func- tions on network devices, akin to how one deploys virtual machines on physical machines in a cloud environment. Such flexibility brings along the threat of unpredictable behavior and performance. What are the minimum restrictions that we need to impose on network functionality such that we are able to verify that a network device behaves and performs as expected, for example, does not crash or enter an infinite loop?...

November 3, 2015 · 1 min · steve ulrich

guess when google showed up at MICE

MICE aggregate traffic graph

June 25, 2015 · 1 min · steve ulrich

sulrich-xtr config archive

sulrich-xtr config archived LISP XTR configuration. no longer operational

June 1, 2014 · 1 min · steve ulrich