Test Wifi Issues
Understanding the Functioning of Internet Addressing
The Internet provides users with either a Public IPv4 address or an IPv6 address, both of which can be checked on https://test-ipv6.com/. However, effectively communicating or identifying MAC addresses like 6f:b7:90:40:7f:d0 can be quite challenging, especially for individuals with limited technical knowledge. This becomes even more complex when attempting to retrieve historical data related to previous problems.
Navigating Web Access
Accessing a web page such as https://fadel.com involves an initial interaction with a DNS server, which translates the host portion (fadel) and the Top Level Domain (com) of the URL into an IP address like 200.78.212.134. Notably, every web request transmitted from a computer and browser includes specific type information, for instance: Opera/9.80 (X11; Linux i686; Ubuntu/14.10) Presto/2.12.388 Version/12.16.
Significance of Default Gateways
Usually acquired through automatic configuration via DHCP, the default gateway serves as the central point where a computer directs all its traffic for further routing. The default gateway address typically takes the form of 192.168.187.173 (usually ending in .1 or .254, depending on the scope size). For IPv6, a detailed analysis is available at how-to-fix-ipv6-connectivity/; one can also perform a check on Mac or Linux.
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 192.168.187.173 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 fe80:4064:7398:f564:c5bc%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): {160.218.229.95, 157.214.30.156}
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 6f:b7:90:40:7f:d0
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 f2:22:4f:96:44:8f
}
Fixing Connectivity Issues for Wired and Wireless Networks
When it comes to sending data to your router, you may be using either a wired or wireless (Wi-Fi) medium at the physical and data layer.
Troubleshooting Tips for Apple macOS / OSX
Regardless of whether you are using OSX/macOS versions such as 10.13.3, 11.3.6, or 12.0.1, there are various tools available for troubleshooting. However, these manual actions and scripts fail to provide a series of correlated values over time. This is where automated remote troubleshooting becomes crucial, particularly for teams that have adopted remote work and Work From Anywhere (WFA) practices.
Utilizing Built-in Scripts
One useful tool in OSX/macOS is sudo wdutil info, which provides a dump of current wireless settings to the CLI and can be configured to generate specific logs for troubleshooting. Furthermore, the sysdiagnose tool can be used to generate a wide range of logs, although much of it is only relevant to wireless issues and is not continuous like wdutil.
Running sudo nohup /usr/bin/sysdiagnose -u & will execute it in the background and write logs to /var/tmp/<blah>.tar.gz. For an interactive run (despite minimal interaction), you can use the command 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. Just be mindful of the file sizes, which are around 300MB.
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