How Do You Test MacOS Connectivity

Understanding Internet Address Allocation When using the Internet, individuals are assigned either a Public IPv4 address, such as 69.215.39.5, or an IPv6 address, like 2000:ce22:fa3f:1600:b65:4ca2:8550:d58c. The validity of these addresses can be verified through https://test-ipv6.com/. However, for those who are not technologically savvy, conveying these addresses or MAC addresses such as 3a:b5:c8:ea:f8:a0 can be prone to errors and quickly become complex. Understanding Internet Address Allocation When using the Internet, individuals are assigned either a Public IPv4 address, such as 69.215.39.5, or an IPv6 address, like 2000:ce22:fa3f:1600:b65:4ca2:8550:d58c. The validity of these addresses can be verified through https://test-ipv6.com/. However, for those who are not technologically savvy, conveying these addresses or MAC addresses such as 3a:b5:c8:ea:f8:a0 can be prone to errors and quickly become complex.

Understanding Internet Address Allocation

When using the Internet, individuals are assigned either a Public IPv4 address, such as 69.215.39.5, or an IPv6 address, like 2000:ce22:fa3f:1600:b65:4ca2:8550:d58c. The validity of these addresses can be verified through https://test-ipv6.com/. However, for those who are not technologically savvy, conveying these addresses or MAC addresses such as 3a:b5:c8:ea:f8:a0 can be prone to errors and quickly become complex. Moreover, this method does not provide any historical data, particularly for resolving past issues.

In order to reach a webpage, such as https://fisher-cormier.org, the initial step involves accessing a DNS server to convert the host portion (fisher-cormier) along with the Top Level Domain (org) of the URL, to an IP address like 191.126.117.100. Moreover, a computer and browser disclose its specifications with every web request, for example: Mozilla/5.0 (Windows; U; Win 9x 4.90; SG; rv:1.9.2.4) Gecko/20101104 Netscape/9.1.0285

Understanding the Significance of Default Gateways

The default gateway is typically an automatically configured address obtained through DHCP. This gateway is usually in the form of an address such as 10.67.64.57 (often ending in .1 or .254 based on the scope size), and serves as the point where a computer sends all its traffic to be routed to other destinations. For IPv6, detailed instructions on how to resolve connectivity issues can be found at how-to-fix-ipv6-connectivity/, and can also be checked on Mac or Linux using the following method:

IPv4 Routes and the Host IPv4 Route Table (inc. VPN)

netstat -rn -f inet | egrep -i "default|0/1|128.0/1"

0/1      172.18.12.193  UGScg  utun3
default  10.67.64.57    UGScg  en0
128.0/1  172.18.12.193  UGSc   utun3

Note: We are not just looking for the default but also for any VPN that overrides the public v4 address space.

IPv6 Routes and the Host IPv6 Route Table (inc. VPN)

netstat -rn -f inet6 | egrep -i "default|2000::/3"

If you have IPv6 active the above should return at least one route (as per below) via a known interface such as “en0 " on a Mac.

default   fe80:8d19:3b16:c7e0:4771%en0  UGcg   en0
default   fe80::%utun0                   UGcIg  utun0
default   fe80::%utun1                   UGcIg  utun1
default   fe80::%utun2                   UGcIg  utun2
2000::/3  utun3                          USc    utun3

Note: We are not just looking for the default but also for any VPN that overrides the public v6 address space.

Debugging DHCP for both IPv4 and IPv6

To get a look at the low level DHCP configuration (Mac/Linux):

ipconfig getpacket en0

...
domain_name_server (ip_mult): {38.145.8.137, 241.111.33.247}
end (none):
...

So, in the above we are not getting IPv6 DNS servers from the DHCPv4 reply but…

ipconfig getv6packet en0

DHCPv6 REPLY (7) Transaction ID 0x80940b Length 76
Options[4] = {
  CLIENTID (1) Length 14: DUID LLT HW 1 Time 668691856 Addr 3a:b5:c8:ea:f8:a0
  DNS_SERVERS (23) Length 32: 2606:4700:4700::1111, 2001:4860:4860::8844
  DOMAIN_LIST (24) Length 0:  Invalid
  SERVERID (2) Length 10: DUID LL HW 1 Addr d4:24:85:97:e9:9c
}

Solutions for Wired and Wireless Connectivity Issues

When it comes to sending data to your router, you might be using a wired or wireless (Wi-Fi) medium at the physical and data layer.

Troubleshooting Techniques for Apple macOS / OSX

Regardless of whether you are using OSX/macOS versions like 10.15.7, 11.3.9, or 12.3.5, there are various troubleshooting tools available. However, these manual actions and scripts do not provide a comprehensive set of correlated values over a period of time. This is where automated remote troubleshooting becomes invaluable, especially for teams that are engaged in remote work and Work From Anywhere (WFA).

Useful Built-in Utilities

One incredibly useful tool on OSX/macOS is the sudo wdutil info command, which provides a dump of current wireless related settings to the command line interface (CLI). This can also be configured to generate specific logs for troubleshooting purposes. Furthermore, the sysdiagnose tool offers a more comprehensive solution by generating a wide range of logs, although much of it is only relevant to wireless networks, similar to wdutil.

Running sudo nohup /usr/bin/sysdiagnose -u & will execute it in the background and save the logs to /var/tmp/<blah>.tar.gz. If you prefer to run it interactively (although there isn’t much interaction), you can use the command
sudo /usr/bin/sysdiagnose, which will prompt a privacy warning. When not run in the background, it should open Finder in the correct location, or you can navigate to /var/tmp using Cmd+Shift+G in Finder. Keep in mind that the file sizes are around 300MB.

Possibly Helpful Videos

Video Title Channel
Secret Mac Boot Commands - Mac Boot Key Combinations Hands-On Mac
On the Road to Big Sur 2 - Compatibility Hands-On Mac
macOS Big Sur - What's New in Apple macOS 11 Hands-On Mac
Spotlight on Spotlight - Hands-On Mac 7 Hands-On Mac
Mac Activity Monitor - How to Troubleshoot Your Mac Hands-On Mac
Table 1.0 - Video Help



P.S. Tips For Remote Network and Client Support

Digital work requires reliable connectivity. Whether for low latency or regular data streams, Wi-Fi, DNS, and network issues cause teams to lose time and productivity. Even worse is when support teams waste time trying to recreate and isolate issues! See how PanSift saves time, money, and frustration on all sides with instant remote troubleshooting 🏠🏝🛰.

Design Benefits + 2 Free Agents


Install on any mobile or stationary Mac for immediate visibility.

Click for a frictionless and instant live demo

2x free agents for problem machines and upgrade for more!

Click for a frictionless and instant live demo

Install as remote sensors at any site or location!

Rapid Digital Experience Monitoring for teams, clients, and sites!

Instant Agent

2 x free macOS agents

Instant Demo

No registration, immediate live demo!