How Can I Test MacOS Internet
The Functioning of Internet Addressing
When using the Internet, you are assigned a Public IPv4 address such as 201.215.176.151 or an IPv6 address like 2000:a4bd:43e6:11b7:bb0e:c7b5:1ec1:f3b. You can verify this information at https://test-ipv6.com/. However, when attempting to convey these addresses to individuals who are not technologically inclined, or when sharing MAC addresses like d5:6f:41:78:f8:a3, errors can occur and it becomes complex. Moreover, it does not provide any historical data about previous issues.
Navigating the Internet
In order to reach a webpage such as https://zboncak.biz, you initially connect to a DNS server to convert the host portion (zboncak) along with the Top Level Domain (biz) of the URL, to an IP address such as 77.80.175.151. Your computer and browser discloses its type with each 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
The Significance of Default Gateways
Your default gateway is typically an automatically configured address via DHCP. You receive a default gateway like 192.0.0.37 (although they generally end in .1 or .254 based on the scope size) and this is where your computer sends all its traffic to be routed onwards. For IPv6, we provide an extensive analysis on how-to-fix-ipv6-connectivity/ but you can verify on Mac or Linux using:
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 192.0.0.37 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 fe80:77ca:5422:5414:b7c4%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): {43.192.159.8, 139.217.2.254}
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 d5:6f:41:78:f8:a3
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 9c:37:83:d1:02:eb
}
Resolving Issues with Wired and Wireless Connections
When it comes to sending data to your router, the physical and data layer offer the choice between a wired or wireless (Wi-Fi) medium.
Troubleshooting Tips for Apple macOS / OSX
No matter which version of OSX/macOS you are using - be it 10.12.5, 11.2.4, or 12.2.4 - there are various tools available for troubleshooting. However, these manual actions and scripts do not provide a series of correlated values over time. This is where automated remote troubleshooting becomes valuable, especially for teams who have embraced remote work and the concept of Work From Anywhere (WFA).
Utilizing Built-in Scripts for Assistance
A very useful tool on OSX/macOS is the sudo wdutil info, which provides a dump to the CLI of current wireless related settings and can also be configured to generate specific logs for troubleshooting. Additionally, the sysdiagnose tool can be used to generate a wide range of logs (although much of it is only related to wireless at a specific point in time, similar to wdutil).
Running sudo nohup /usr/bin/sysdiagnose -u & will execute the tool in the background and write the logs to /var/tmp/<blah>.tar.gz. If you prefer to run it interactively, you can use sudo /usr/bin/sysdiagnose, which will result in 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 Finder with Cmd+Shift+G to point to the path. Keep in mind that the file sizes are approximately 300MB, more or less.
Possibly Helpful Videos
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 🏠🏝🛰.
