Posts in 2020

  • nginx ISP fence

    Tuesday, September 01, 2020 in Systems

    Sometimes the easiest way to geo fence an application is to just whitelist certain ISP’s networks only. Nginx has a handy way to map IPs into subnets using the geo module. Requirements job/aggregate6 to aggregate/unique-ify the prefix lists …

    Read more

  • OpenBSD 6.6 BGP Looking Glass

    Tuesday, April 14, 2020 in BGP

    I’ve written about OpenBSD and BGP Looking Glasses previously and before that. OpenBSD has since removed nginx from base, and replaced it with their own httpd. This is OK with me since I prefer having my OpenBSD systems fully self-contained and …

    Read more

  • MPLS Labels Explained

    Saturday, February 01, 2020 in MPLS

    I had a (perhaps common) misunderstanding about how MPLS applied labels. I thought that MPLS would stack up labels for the entire path (so like 6 hops, 5 labels). This of course would affect MTU of MPLS packets, especially on the originating edge. …

    Read more

  • Troubleshooting a Duplicate OSPF Router ID

    Wednesday, January 29, 2020 in Troubleshooting

    Keywords: Troubleshooting, OSPF, Router ID, MPLS, VPLS Introduction I ran into an strange issue today. The problem was reported as “can’t upload on a speed test”. I started looking into the reported speed test issue by doing my …

    Read more

  • Centrally Managed WiFi with MikroTik CAPsMAN

    Sunday, January 19, 2020 in MikroTik

    Keywords: WiFi, Managed WiFi, CAPsMAN, MikroTik, VLAN Introduction MikroTik has been known in the WISP wireless world for a long time for their wireless PTP and PTMP products. However more recently they have also started making WiFi products aimed …

    Read more

Posts in 2019

  • An Exercise in Systems Thinking or Stupidity... Your Choice

    Tuesday, May 28, 2019 in Guest Blogs

    I was recently read into a Problem for which the particular vendor was downplaying the severity of the issue and the usual games of Enterprising ‘saving face.’ They were haranged into providing a means for detecting the failure state and …

    Read more

  • Inadvertent Transit

    Thursday, April 25, 2019 in Networking

    This blog post is about an actual real life, local network situation that happened several days ago. This is an excellent learning example about a perfect storm of small things causing a network outage. It is also an excellent learning example of how …

    Read more

  • Fastnetmon on Ubuntu 18.04

    Saturday, February 09, 2019 in Networking

    I’ve spent some time trying to manually install Fastnetmon community edition on Ubuntu 18.04 Bionic Beaver. I was unsuccessful. However, I didn’t do an apt-cache search fastnetmon. There is a package in universe. Bionic Beaver also …

    Read more

  • MRT Dumps with GoBGP

    Wednesday, January 30, 2019 in Networking

    I’ve been logging BGP route updates into MySQL for some time but this doesn’t scale well, and on my hobby VM system, requires that I dump the DB and start over once a day. One of the things I’ve wanted to do for a long time is to be …

    Read more

Posts in 2018

  • The Road to MPLS

    Wednesday, September 26, 2018 in MPLS

    This year I’ve build two totally different MPLS Service Provider networks. One network has limited MPLS with VPLS on MikroTik, the other is a full MPLS L3VPN on HPE Comware gear. Articles in this Series Normally MPLS is abstracted out on …

    Read more