Test Apple Internet
Understanding Internet IP Addressing
When using the Internet, you are assigned a unique Public IPv4 or IPv6 address, such as 20.59.230.33 or 2000:e451:790a:91f3:c811:9b6f:3592:fbdf. These addresses can be verified at https://test-ipv6.com/. However, for those unfamiliar with technical jargon, communicating these addresses or MAC addresses like 00:b2:88:7e:1f:21 can be prone to errors and quickly become complex. Furthermore, these addresses do not provide any historical data, particularly when dealing with past issues.
Navigating the World Wide Web
Accessing a web page, such as https://cummings-schoen.info, involves initially contacting a DNS server to convert the host portion (cummings-schoen) along with the Top Level Domain (info) of the URL into an IP address, for example 171.11.125.215. Your computer and browser include information about its type in all web requests, such as Opera/9.80 (X11; Linux i686; Ubuntu/14.10) Presto/2.12.388 Version/12.16
The Significance of Default Gateways
The default gateway is typically an automatically assigned address through DHCP, which could be something like 172.23.19.180 (commonly ending in .1 or .254 depending on the scope size). This is where your computer sends all its traffic to be routed onwards. For IPv6, more detailed information is available in our post how-to-fix-ipv6-connectivity/, and can also be checked on Mac or Linux using 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 172.23.19.180 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 b39e:b0e1:a0:fe32:4163:d75a:5fca:d628%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): {221.85.178.177, 88.30.179.135}
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 00:b2:88:7e:1f:21
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 5c:2f:6d:8e:53:2f
}
Resolving Connectivity Issues for Wired and Wireless Networks
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.
Troubleshooting Guidelines for Apple macOS / OSX
Regardless of whether you are using OSX/macOS versions like 10.14.8, 11.3.2, or 12.1.9, there are several troubleshooting tools available. However, these manual actions and scripts do not provide a set of correlated values over time. This is where automated remote troubleshooting becomes invaluable, especially for teams that adopt remote work and Work From Anywhere (WFA) policies.
Useful Built-in Utility Scripts
One of the useful tools for OSX/macOS is sudo wdutil info, which provides a dump of the current wireless settings to the CLI and can be configured to generate specific troubleshooting logs. Additionally, the sysdiagnose tool can be used to generate a wide range of logs, although much of it is related to wireless settings at a specific point in time, similar to wdutil.
Running sudo nohup /usr/bin/sysdiagnose -u & in the background will write logs to /var/tmp/<blah>.tar.gz. If you prefer to run it interactively, you can use sudo /usr/bin/sysdiagnose, which will prompt 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 Cmd+Shift+G in Finder. Keep in mind that the file sizes are around 300MB or so.
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 🏠🏝🛰.
