Test Wifi Internet Issues

Understanding the Operation of Internet Addresses When using the Internet, it is possible to have a Public IPv4 address such as 153.8.92.10 or an IPv6 address like 2000:d74d:27bb:28e:eb6e:a146:af76:d8e1. This can be verified at https://test-ipv6.com/. However, explaining or using these addresses, as well as calling out MAC addresses like dd:bc:61:ca:dd:fb, can be prone to errors and becomes complex quickly. Understanding the Operation of Internet Addresses When using the Internet, it is possible to have a Public IPv4 address such as 153.8.92.10 or an IPv6 address like 2000:d74d:27bb:28e:eb6e:a146:af76:d8e1. This can be verified at https://test-ipv6.com/. However, explaining or using these addresses, as well as calling out MAC addresses like dd:bc:61:ca:dd:fb, can be prone to errors and becomes complex quickly.

Understanding the Operation of Internet Addresses

When using the Internet, it is possible to have a Public IPv4 address such as 153.8.92.10 or an IPv6 address like 2000:d74d:27bb:28e:eb6e:a146:af76:d8e1. This can be verified at https://test-ipv6.com/. However, explaining or using these addresses, as well as calling out MAC addresses like dd:bc:61:ca:dd:fb, can be prone to errors and becomes complex quickly. Moreover, this does not provide any historical data, especially when addressing past issues.

In order to access a website such as https://schumm-emard.co, the initial step is to access a DNS server to convert the host portion (schumm-emard) combined with the Top Level Domain (co) of the URL, into an IP address like 195.93.222.152. The computer and browser sends its type with all web requests, for example:
Mozilla/5.0 (Windows; U; Win 9x 4.90; SG; rv:1.9.2.4) Gecko/20101104 Netscape/9.1.0285

Significance of Default Gateways

The default gateway is usually an address configured automatically via DHCP, such as 172.16.159.40 (although they generally end in .1 or .254 depending on the scope size). This is the point where a computer sends all its traffic to be routed onwards. For IPv6, an in-depth discussion is available at how-to-fix-ipv6-connectivity/, with the ability to check on Mac or Linux using the following code:

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  172.16.159.40    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:a8b2:a754:8d80:f9f1%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): {249.53.80.19, 101.239.34.242}
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 dd:bc:61:ca:dd:fb
  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 22:5e:8f:7c:31:15
}

Solutions for Resolving Wired and Wireless Connectivity Issues

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

Steps to Take on Apple macOS / OSX Devices

Regardless of whether you are running OSX/macOS versions such as 10.15.7, 11.4.5, or 12.2.9, there is a wide range of troubleshooting tools available. However, these tools and scripts do not provide a set of correlated values over time, making automated remote troubleshooting an essential solution, particularly for teams that embrace remote work and Work From Anywhere (WFA).

Useful Built-in Scripts

A very handy tool on OSX/macOS is the sudo wdutil info, which dumps current wireless related settings to the CLI and can be configured to generate specific logs for troubleshooting. Additionally, the sysdiagnose tool can be used to generate a variety of logs, although much of it is only related to wireless at a specific point in time, much like wdutil.

To run it in the background and write logs to /var/tmp/<blah>.tar.gz, use the command sudo nohup /usr/bin/sysdiagnose -u &. For an interactive run (although there is not much interaction), use the command sudo /usr/bin/sysdiagnose, which will give a privacy warning. When not run in the background, it should open Finder in the correct location, or you can navigate to /var/tmp or use Finder with Cmd+Shift+G to point Finder to the path. However, be aware of the file sizes, which are approximately 300MB.

Possibly Helpful Videos

Video Title Channel
Hotspot 2.0 WLPC Wireless LAN Weekly EP 49 Wireless LAN Professionals
Wi Fi Issues in the Wild Gopinath K.N. WLPC Phoenix 2018 Wireless LAN Professionals
Benefits of WPA3, Enhanced Open, and Easy Connect P. Ebbecke, P. Correll WLPC Prague 2018 Wireless LAN Professionals
TIP OpenWifi Demo Network Setup for WLPC Drew Lentz WLPC Prague 2022 Wireless LAN Professionals
Apples to Apples: An Analysis of the Effects of mDNS Traffic Bryan Ward WLPC Phoenix 2023 Wireless LAN Professionals
Table 1.0 - Video Help



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