How Do You Support MacOS Internet
Understanding Internet Addressing
When connecting to the Internet, you are assigned a unique Public IPv4 or IPv6 address, such as 21.102.169.190 or 2000:a111:9b1e:1546:b9ef:1549:4834:45ee. Verifying this information can be done at https://test-ipv6.com/. However, conveying these addresses or MAC addresses like c8:56:3b:65:2b:d4 to non-technical individuals can become complex and prone to errors, while also lacking historical data.
Initiation of Web Access
When attempting to access a website like https://russel-kovacek.org, your computer first communicates with a DNS server to convert the host portion (russel-kovacek) and the Top Level Domain (org) of the URL into an IP address, such as 183.35.227.85. Furthermore, the type of your computer and browser is sent with every web request, as demonstrated by Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_3) AppleWebKit/537.75.14 (KHTML, like Gecko) Version/7.0.3 Safari/7046A194A
Significance of Default Gateways
By default, your computer obtains a gateway address automatically via DHCP, typically in the form of 10.64.211.173 (commonly ending in .1 or .254 depending on scope size). This gateway serves as the destination for all outbound traffic from your computer. For IPv6 related troubleshooting, detailed information can be found at how-to-fix-ipv6-connectivity/, while Mac or Linux users can perform checks 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 10.64.211.173 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 fe80:9738:5aca:28d7:421a%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): {22.219.192.206, 106.214.246.47}
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 c8:56:3b:65:2b:d4
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 bc:d4:0d:2d:93:28
}
Fixing Connectivity Issues for Wired and Wireless Networks
When it comes to transmitting data to your router, you may be using a wired or wireless (Wi-Fi) medium at the physical and data layer.
Resolving Problems on Apple macOS / OSX Devices
Regardless of whether you are running MacOS/OSX versions such as 10.15.7, 11.4.6, or 12.1.3, there are various troubleshooting tools available. 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 that embrace remote work and Work From Anywhere (WFA).
Utilizing Built-in Tools for Assistance
A very useful tool on OSX/macOS is the sudo wdutil info command, which provides a dump of the current wireless settings to the command line interface. It can also be configured to generate specific logs for troubleshooting purposes. Furthermore, the sysdiagnose tool can be used to generate a wide range of logs in a more comprehensive manner, although many are point-in-time related to wireless, similar to wdutil.
To run sysdiagnose in the background and write logs to /var/tmp/<blah>.tar.gz, use the command sudo nohup /usr/bin/sysdiagnose -u &. If you prefer to run it interactively, use sudo /usr/bin/sysdiagnose and be aware of the file sizes of about 300MB. Additionally, the command will provide a privacy warning and open Finder in the correct location, or you can navigate to /var/tmp using Finder with Cmd+Shift+G.
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 🏠🏝🛰.
