Networking
PCC load balancing without breaking online banking
Per-connection classifier is the right tool, but the default configuration will log users out of session-sensitive sites. Here is the marking scheme we use instead.
Field notes
What we learn on site, written down
Notes from actual deployments — the failure modes, the configuration decisions we revised, and the operational habits that turned out to matter more than the hardware.
Networking
Why your failover has never actually been tested
Pulling the WAN cable is not a failover test. What a partial failure looks like, why check-gateway alone is not enough, and the verification sequence we run at handover.
ISP Operations
Collection rate is a notification problem
Most ISPs treat late payment as a discipline issue. In the deployments we have measured, a three-day reminder moves the number more than any penalty structure.
Networking
Queue trees: getting HTB parents right
The common mistake is setting the parent limit to your subscribed capacity. What to set it to instead, and how burst interacts with the leaves below it.
Security
Moving a branch network from IPsec to WireGuard
What we gained, what we had to rethink about routing policy, and the one thing that caught us out during the cutover on a live retail network.
Networking
Bridge VLAN filtering, explained once properly
Tagged, untagged, PVID and the hardware-offload conditions on CRS switches — with the config that actually survives a reboot.
Software
The spreadsheet is the specification
When a client hands us the sheet their business actually runs on, it contains every business rule they forgot to mention. How we read it before writing code.
Software
Sending SMS at scale without a carrier contract
How the PingNotify Android gateway handles queueing, rate limits and device failover — and the volume ceiling where a proper aggregator becomes the right answer.
Hardware
Sizing a router by PPS, not by port count
Marketing throughput assumes 1500-byte frames and an empty firewall. How to estimate what your traffic profile really needs before you buy.
Stay in the loop
New field notes, roughly monthly
No newsletter marketing. Just a note when we publish something worth the ten minutes.