Open in app

Sign In

Write

Sign In

One9twO
One9twO

3 Followers

Home

About

2 days ago

Tips for troubleshooting an RO filter system

I have RO filters installed under kitchen sink over the past 7 years. I have replaced many filters (stage 1–3 filters every few months, membrane every year or two). Sharing some tips after years of hands-on experience. The model I have is this one: APEC Water Systems ROES-50 Essence Series Top Tier 5-Stage Certified Ultra Safe Reverse Osmosis Drinking Water Filter System, 50 GPD https://www.amazon.com/APEC-5-Stage-Reverse-Drinking-Water/dp/B00I0ZGOZM

Reverse Osmosis

4 min read

Reverse Osmosis

4 min read


Nov 16, 2022

TryHackMe WriteUp: Templates

Here’s a write up for https://tryhackme.com/room/templates Recon After starting up the machine, as per instruction there’s a website running on port 5000. In my case: http://10.10.33.8:5000/ Click on the Convert to HTML button, it’ll convert the template to HTML. To make it easier to visualize the request, I replaced the…

Ctf

2 min read

TryHackMe WriteUp: Templates
TryHackMe WriteUp: Templates
Ctf

2 min read


Nov 10, 2022

Docker Desktop Port ‘Not bound’

This turns out to be my command line error. The arguments of docker run need to follow the right order. i.e. This will ignore the port mapping: docker run 09dad155f3cc -d -p 8080:8080/tcp and this will work as expected: docker run -p 8080:8080/tcp 09dad155f3cc -d

Docker

1 min read

Docker Desktop Port ‘Not bound’
Docker Desktop Port ‘Not bound’
Docker

1 min read


Nov 10, 2022

A Docker Error on Mac

When building a Dockerfile from my MacBook: > docker build . Sending build context to Docker daemon 123kB Step 1/8 : FROM debian:jessie jessie: Pulling from library/debian no matching manifest for linux/arm64/v8 in the manifest list entries A quick search of the error “no matching manifest for linux/arm64/v8 in the manifest list entries” indicates it has to do with Apple M1 Chip. Workaround Pull the image with the platform specified:

Docker

1 min read

Docker

1 min read


Oct 5, 2022

SSH: DDoS mitigation

In sshd_config, there’s a configuration parameter for MaxStartups. The man page: MaxStartups Specifies the maximum number of concurrent unauthenticated connections to the SSH daemon. Additional connections will be dropped until authentication succeeds or the LoginGraceTime expires for a connection. The default is 10:30:100. Alternatively, random early drop can be enabled…

Ssh

3 min read

Ssh

3 min read


Aug 11, 2022

Ruby gem exception: invalid option

Below is my ‘quick fix’ (bandaid) solution to the following errors/exceptions. The errors Error: Execution of '/usr/bin/gem install --no-rdoc --no-ri cowsay' returned 1: ERROR: While executing gem ... (OptionParser::InvalidOption) invalid option: --no-rdoc Did you mean? no-force A reference article https://github.com/puphpet/puphpet/issues/2838 The ‘quick fix’ W.r.t. the reference article, I searched for the file ‘gem.rb’. Since ‘locate’ was not installed in the OS, I used the ‘find’ command to look for the file:

Ruby

1 min read

Ruby

1 min read


Aug 10, 2022

Puppet manifest not pulling

Continued from the previous post. As I am making full use of my 30-days free account in Azure, I have setup a pair of Puppet servers to test (with respect to the reference article at the bottom). A problem In the Puppet master, I have: /etc/puppet/manifests/site.pp with content file {'/tmp/example-ip'…

Puppet

1 min read

Puppet

1 min read


Aug 6, 2022

Azure Cloud Free Tier

I have just started using Azure cloud. As a frugal engineer, I will make full use of the 30 days free tier. As I added more VMs to my free account, it finally hit the limit. On the Virtual Machines page, I could not find a button to downsize the ones I already created (even if I power the VM down). So I started deleting them to free up the limit. But the following error persisted, even after I deleted every VM/refreshed the page:

Azure

1 min read

Azure Cloud Free Tier
Azure Cloud Free Tier
Azure

1 min read


Jul 21, 2022

Protectli Vault + pfSense

Lately I have tested Protectli Vault (with both OPNsense and pfSense). Below are some tips/takeaways. Protectli Vault The model I tested was FW6D — 6 Port Intel® i5. Protectli Vault - 6 Port Ports, power, customization: Meet the 6-Port Vaults, ideal for businesses and complex networks: Intel 3867U, i3-7020U…protectli.com Why Protectli Due to some physical constraints (of the place where my ISP placed the cable), I need a firewall without a lot of fan noise…

Firewall

4 min read

Protectli Vault + pfSense
Protectli Vault + pfSense
Firewall

4 min read


May 28, 2022

Graylog Dashboard for Nginx Logs

Graylog is a great tool to visualize and analyze what’s happening to your backend systems. Production log files are usually too noisy for human eyes, i.e. a tail -f on the log will show you the influx of new entries which are impossible for human eyes to catch. Moreover, logs…

Graylog

2 min read

Graylog

2 min read

One9twO

One9twO

3 Followers

A pragmatic programmer with a rubber duck.

Help

Status

Writers

Blog

Careers

Privacy

Terms

About

Text to speech