Test Apple Internet Connection

Understanding Internet Addressing

When connecting to the Internet, you are assigned a unique Public IPv4 address, such as 81.139.7.178, or an IPv6 address like 2000:8dba:2802:271a:55d:c331:6064:5276. You can verify your address at https://test-ipv6.com/. However, explaining and managing these addresses, as well as MAC addresses like e2:07:78:6d:f2:c6, can be complicated and prone to errors, especially for non-technical individuals. Additionally, historical data is not readily available, especially for past issues.

Navigating the World Wide Web

In order to access a website, such as https://murray.co, your computer first contacts a DNS server to convert the host portion (murray) and the Top Level Domain (co) of the URL into an IP address, like 112.124.120.186. When making web requests, your computer and browser also provide their type, for example
Mozilla/5.0 (Windows NT x.y; Win64; x64; rv:10.0) Gecko/20100101 Firefox/10.0

Understanding the Role of Default Gateways

Your default gateway is typically assigned automatically through DHCP and may appear as an address like 10.232.167.45 (usually ending in .1 or .254 based on the scope size). This gateway is where your computer sends all of its traffic to be routed further. For IPv6, detailed instructions can be found at how-to-fix-ipv6-connectivity/, and it can be checked on Mac or Linux by 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  10.232.167.45    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   fe80:5317:b4e:e25:1a68%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): {242.239.107.83, 195.246.5.130}
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 e2:07:78:6d:f2:c6
  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 eb:5d:92:71:08:bc
}

Solutions for Resolving Issues with Wired or Wireless Networks

When dealing with the physical and data layer of network connections, you may be utilizing either a wired or wireless (Wi-Fi) medium to transmit data to your router.

Resolving Problems on Apple macOS / OSX Systems

Regardless of the version of OSX/macOS you are using, whether it’s 10.13.7, 11.0.7, or 12.3.9, 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 comes in handy, particularly for teams that prioritize remote work and Work From Anywhere (WFA) arrangements.

Useful Built-in Scripts for Assistance

An extremely beneficial tool on OSX/macOS is the sudo wdutil info, which provides a dump of current wireless related settings to the command line interface, and can also be configured to generate specific logs for troubleshooting. Additionally, the sysdiagnose tool offers a more comprehensive option for generating a wide range of logs (though much of it is only relevant to wireless settings, similar to wdutil).

Running sudo nohup /usr/bin/sysdiagnose -u & in the background will write the logs to /var/tmp/<blah>.tar.gz for you. If you prefer to run it interactively (although there isn’t much interaction), you can execute
sudo /usr/bin/sysdiagnose, which will prompt a privacy warning. If not run in the background, it should open Finder in the correct location, or you can navigate to /var/tmp, or use Finder with Cmd+Shift+G to point Finder to the path. It is important to be aware of the file sizes, which are around 300MB on average.

Possibly Helpful Videos

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Table 1.0 - Video Help