How Do You Support Mac Connectivity

Understanding Internet Addressing

When using the Internet, your device may be assigned a Public IPv4 address, such as 95.197.34.216, or an IPv6 address, like 2000:564f:2d12:fe91:8192:40b4:3899:8365. You can verify this by visiting https://test-ipv6.com/. However, conveying these addresses, or even mentioning MAC addresses like 0e:33:61:b7:4c:af, to those unfamiliar with technical details can be challenging and error-prone, especially when attempting to recount historical data related to past issues.

Navigating the Online Environment

When accessing a website such as https://cummings-rippin.org, your computer initially communicates with a DNS server in order to translate the host portion (cummings-rippin) combined with the Top Level Domain (org) of the URL into an IP address, like 185.107.34.34. Additionally, your computer and web browser provide information about their type with every web request, for instance:
Mozilla/5.0 (compatible; MSIE 9.0; AOL 9.7; AOLBuild 4343.19; Windows NT 6.1; WOW64; Trident/5.0; FunWebProducts).

The Significance of Default Gateways

Typically, your default gateway is an automatically configured address assigned via DHCP, such as 172.30.75.211 (commonly ending in .1 or .254 based on the scope size). This is the location to which your computer sends all of its traffic to be routed onwards. For IPv6, you can further explore this topic in our in-depth article on how-to-fix-ipv6-connectivity/. Alternatively, on Mac or Linux, you can verify this with:

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  172.30.75.211    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:f97c:6f34:3fd9:73f8%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): {186.27.247.240, 178.74.117.125}
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 0e:33:61:b7:4c:af
  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 f3:06:d8:40:9f:03
}

Solve Issues with Wired and Wireless Connections

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

Effective Solutions for Apple macOS / OSX

No matter which version of OSX/macOS you are operating on, whether it’s 10.13.4, 11.5.8, or 12.1.7, there are numerous 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 essential, especially for teams that adopt remote work and Work From Anywhere (WFA) practices.

Useful Built-in Tools for Troubleshooting

One particularly useful tool on OSX/macOS is sudo wdutil info, which offers a dump to the CLI of current wireless related settings and can be configured to generate specific logs for troubleshooting purposes. Furthermore, the sysdiagnose tool can be used to generate a wide range of logs, although much of it is only relevant to wireless settings, similar to wdutil.

To run sysdiagnose in the background and write logs to /var/tmp/<blah>.tar.gz, you can use the command sudo nohup /usr/bin/sysdiagnose -u &. For an interactive run (though there is minimal interaction), you can run sudo /usr/bin/sysdiagnose and it will provide a privacy warning. If not run in the background, it should open Finder in the correct location, allowing you to navigate to /var/tmp, or you can use Finder with Cmd+Shift+G to navigate to the path. It’s important to note that the file sizes are approximately 300MB.

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Table 1.0 - Video Help