Support Apple Connectivity

Understanding Internet Addressing

When connecting to the Internet, you are assigned a Public IPv4 address, such as 184.174.173.226, or an IPv6 address, such as 2000:f952:8bb0:b102:fca2:941:55c8:5202. This can be verified at https://test-ipv6.com/. However, translating and communicating these addresses, as well as MAC addresses like 7e:5b:90:4f:11:53, can be challenging for individuals without technical expertise. Moreover, this method lacks historical data, particularly from previous issues.

The Process of Accessing the Internet

When attempting to access a website, for example, https://klein.info, your computer first contacts a DNS server to convert the host part (klein) and the Top Level Domain (info) of the URL into an IP address, such as 98.152.221.187. Moreover, your computer and browser automatically include its type in all web requests, such as
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

Usually, your default gateway is an automatically configured address provided through DHCP. This default gateway, such as 10.108.134.160 (often ending in .1 or .254 depending on the scope size), is where your computer sends all of its traffic to be routed onwards. For IPv6, a detailed explanation can be found in our article how-to-fix-ipv6-connectivity/. Additionally, 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  10.108.134.160    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   fe80:860d:cb1f:11b1:17d6%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): {235.143.133.93, 221.125.17.131}
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 7e:5b:90:4f:11:53
  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 33:e2:2e:8f:ca:38
}

Resolve Issues with Wired and Wireless Connections

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

Troubleshooting Methods for Apple macOS / OSX

Regardless of whether you are using OSX/macOS version 10.14.1, 11.3.6, or 12.3.7, there are various tools available for resolving issues. However, these manual methods and scripts do not provide a set of correlated values over time. This is where automated remote troubleshooting proves to be extremely useful, especially for teams that are embracing remote work and the Work From Anywhere (WFA) approach.

Pre-Installed Tools That Can Offer Assistance

One particularly useful tool on OSX/macOS is the command sudo wdutil info, which provides a comprehensive dump of the current wireless settings to the CLI and can also be configured to generate specific logs for troubleshooting purposes. Additionally, the sysdiagnose tool can be used to generate a wide range of logs, although many of them are only relevant to a specific point in time in relation to wireless, similar to wdutil.

Running sudo nohup /usr/bin/sysdiagnose -u & will execute the tool in the background and write logs to /var/tmp/<blah>.tar.gz for you. If you prefer to run it interactively (even though there is limited interaction), you can use the command
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. However, be cautious of the file sizes, which are approximately 300MB or slightly more.

Possibly Helpful Videos

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

Table 1.0 - Video Help