How Do You Support Mac Internet Connection
Understanding the Function of Internet Addressing
When using the Internet, you are assigned either a Public IPv4 address, such as 160.74.114.77, or an IPv6 address like 2000:a5b8:4d7b:b18:fba2:d487:e3c8:a70. This information can be verified at https://test-ipv6.com/. However, explaining these addresses or referencing MAC addresses like c3:ef:8b:e0:ca:c8 to those who are not familiar with technology can be prone to errors and becomes complex rather quickly. Moreover, this method does not provide historical data, particularly when past issues arise.
Navigating Through the Internet
In order to reach a website such as https://bauch.net, your first step is to connect to a DNS server to translate the domain name (bauch) in combination with the Top Level Domain (net) of the URL into an IP address, such as 124.75.62.223. Your computer and browser include their types with all web requests, such as Mozilla/5.0 (Windows NT x.y; Win64; x64; rv:10.0) Gecko/20100101 Firefox/10.0.
Significance of Default Gateways
Your default gateway is typically automatically configured through DHCP and is assigned an address such as 10.50.224.207 (although they commonly end in .1 or .254 based on the scope size). This is the location where your computer routes all of its traffic for further transmission. To explore further on IPv6, you can refer to our in-depth guide on how-to-fix-ipv6-connectivity/, or check on Mac or Linux utilizing the following command:
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 10.50.224.207 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:c4a9:31ec:a1aa:fd15%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): {172.80.64.188, 77.161.104.9}
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 c3:ef:8b:e0:ca:c8
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 bb:81:d2:f4:00:87
}
Resolve Issues with Wired and Wireless Connections
When it comes to transmitting data to your router, you might be using either a wired or wireless (Wi-Fi) medium at the physical and data layer.
Actions to Take on Apple macOS / OSX Systems
Regardless of whether you are using OSX or macOS versions such as 10.12.3, 11.5.7, or 12.3.5, there are various troubleshooting tools available. However, these manual actions and scripts do not provide a set of correlated values over a period of time. This is where automated remote troubleshooting becomes valuable, especially for teams that are engaged in remote work and Work From Anywhere (WFA).
Useful Built-in Scripts
On OSX/macOS, the sudo wdutil info tool is quite helpful as it provides a dump of current wireless settings to the CLI and can also be configured to generate specific logs for troubleshooting. In addition, the more comprehensive sysdiagnose tool can be used to generate a wide range of logs, although many are only relevant to wireless at a specific point in time, similar to wdutil.
Running sudo nohup /usr/bin/sysdiagnose -u & in the background will create logs in /var/tmp/<blah>.tar.gz for you. If you prefer to run it interactively (although there is not much interaction), you can executesudo /usr/bin/sysdiagnose with 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. However, be aware of file sizes, which can be around 300MB.
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