Michael Bianco

Understanding DNS Requests on macOS

The DNS Stack Here’s a quick overview of how the DNS stack on macOS works. Much of this also applies to linux. cat /etc/resolv.conf contains a list of potential DNS resolvers DNS servers work off of UDP (not TCP) on port 53, but at this point, there are multiple DNS protocols that use different ports and configurations. You can see the DNS resolvers assigned to a specific device using scutil –dns This list is autogen’d and managed by the DNS settings of the current network device Unlike linux variants, this is not managed by NetworkManager and instead uses macOS-specific tooling, much of which is opaque…

Fast, Local, Written-by-you Code Search

I work with many disparate open-source repos in many different programming languages. I often encounter a problem that I know I’ve solved before, but I can’t remember where I solved it. When I worked at Stripe, we had livegrep. It searched all of the repositories across Stripe in real-time. GitHub has an awesome code search tool now too. I love code search: often, it’s easier to "grep the internet" for obscure usage examples than asking ChatGPT or Google. However, what was missing was a code search tool I could quickly run on the command line to search through local Git repositories that were mostly written by me…

Notes on the NetSuite CustomerDeposit Record

In the past, I worked a lot with the NetSuite CustomerDeposit record. Like most things in NetSuite, there are many nuances that can waste a lot of your time. Here are some the things I learned: Searching for CustomerDeposits with the _customerDepositNotDeposited status will not return results that cannot be deposited, but it will not return all deposits that can be deposited. When a CustomerDeposit is applied against an Invoice or a CustomerRefund, a DepositApplication record is created. The deposit field links to the CustomerDeposit. There is an applyList which applies the deposit to invoices or customer refunds. When a DepositApplication is created the status of a CustomerDeposit shifts to FullyApplied…

Inspecting Network Traffic on macOS

I ran into a scenario where I wanted to sniff out exactly what was being communicated by a macOS app. It’s been a long time since I’ve done any http sniffing so it great to try out some new tools. Packet Sniffing Packet sniffing is the easiest way to see what is happening on your network device. No sudo, no proxies. However, you can only see the domain being contacted for SSL requests. Great for high level activity, not great for understanding the details of what an application is doing on your computer. Using a Proxy to Inspect HTTPS Traffic In order to view HTTP traffic, you need to route all network traffic on your device through a proxy. mitmproxy is exactly what you need…

My Ergonomic Desk Setup

Years ago, I had wrist issues. After a certain point, they would just constantly hurt. Since then I’ve always tried to iterate on my desk setup each year. I sit at my computer typing a lot; investing in the tools I use every day always made a bunch of sense. I’ve spent time & money researching, purchasing, testing, etc various tools to improve my desk setup to eliminate pain. Notes from an Ergonomic Consultation One of the neat things my BigTech job provided was a session with an ergonomic consultant. Here are some notes: The screen should be at arm’s length from your body. Most likely, you should pull your screen closer to your face. The knees should be at or below the hip level. This means your desk and chair should sit lower…

Automatically Download and Rename Your LabCorp PDFs

Over the last couple of years, I’ve incrementally tried to improve my understanding of my health. Part of this is understanding my lab work and collecting the data in a way that I can personally understand and analyze it. In order to do this, I needed to download all of my past LabCorp PDFs. My goal in downloading these PDFs is to funnel them into my custom GPT, which will extract the results into a nicely formatted CSV that I can then copy and paste into Google Sheets. This enables me to easily graph, chart, and otherwise analyze my blood work results. Given the lack of a straightforward way to download all PDFs from the LabCorp website, I created scripts to automate the downloading and renaming of the PDFs for easier analysis and storage…

How to Inject Custom Code on Python Interpreter Startup

Ruby and Javascript both allow you to execute arbitrary code before your main application runs without modifying your application code. My most common use case is executing monkey patches to make it easier to debug an application. However, this is not possible with Python. This makes using development tools like pretty-traceback challenging. In my case, I work across a bunch of reports, and injecting six lines of Python into each repo is annoying (especially since many open-source repos don’t have a concept of a PYTHON_ENV, so there’s not an easy way to disable it in prod). The Magic .pth File In any engineering discipline, the more you understand the entire stack you are working with, the faster you’ll be able to fix issues…

What I’ve Learned Searching for a New Startup Idea, Part 3

This is part 3 of a series of blog posts (here’s part 1 & part 2) about what I’m learning as I hunt for a new startup idea to work on). PE Rollups Create Opportunity Private equity is rolling up every industry you can imagine 1 . Plumbers, electricians, dental offices, primary care offices, machine shops, lawn businesses, RV parks, and software. PE is brilliant at extracting returns from an unoptimized business. It’s bad at focusing on the customer and building a great product. As industries roll up, prices increase, the quality of service decreases, and opportunities for a new disruptor at the bottom of the market emerge. Why does this happen? When PE acquires a business, the original founders lose motivation…

How I Think About Insurance Products

Following up on my financial directives post, here are some of my thoughts about insurance. Nearly everyone has to purchase multiple insurance policies. It’s a constant cost you’ll have your entire financial life. It’s worth spending some time optimizing. Friends and family have asked me about this multiple times, so I’ve slowly compiled my notes for them. Here they are! Don’t Prepay, Self-Insure Instead I like to think of insurance as something you most likely never have to use. If you expect to use insurance, you’ll pay for it in increased premiums and the insurance companies will come out ahead. Then, it’s not really insurance, it’s prepayment for services you are going to use…

Vertical SaaS is Dead

Ok, not completely, but it’s a catchy headline, huh? Last year, I set out to find a new startup idea with a straightforward thesis: There’s important B2B SaaS software to build. It’s easy to feel like so much software has been built, but if you look under the surface, there’s so much that’s broken. There’s much opportunity to build B2B SaaS—especially for underserved markets. Specific markets are grossly underserved by technology. For instance, founders and engineers don’t generally build for civil engineers or landscape architects, but developers love building devtools and infrastructure. If we build modern software for these underserved markets, they’ll eagerly adopt it…

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