Support Wifi Router Issues

Understanding Internet Protocol Addresses

When using the Internet, you will be assigned a Public IPv4 address, such as 232.186.116.85, or an IPv6 address, such as 2000:5783:4ac0:17:b6ef:78aa:2db6:c106. These addresses can be verified at https://test-ipv6.com/. Communicating these addresses, including MAC addresses like 48:84:44:fd:88:e5, can be prone to errors and complexities, particularly for individuals who are not tech-savvy. Moreover, it does not provide any historical data, especially when past issues arise.

Navigating the World Wide Web

In order to access a website, such as https://witting-funk.biz, you first connect to a DNS server to convert the host portion (witting-funk) and the Top Level Domain (biz) of the URL into an IP address, like 38.48.66.27. Every web request made by your computer and browser contains its type, indicated by
Opera/9.80 (X11; Linux i686; Ubuntu/14.10) Presto/2.12.388 Version/12.16.

Understanding the Significance of Default Gateways

Derived from DHCP, your default gateway is typically assigned as an automatically configured address. It could be something like 10.146.169.40 (frequently ending in .1 or .254, depending on the scope size), and it serves as the point where your computer forwards all its traffic to be routed further. For IPv6, more in-depth information can be found at how-to-fix-ipv6-connectivity/, while Mac or Linux can be checked 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  10.146.169.40    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:fb47:7745:a84c:2ca4%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): {143.128.217.157, 242.119.141.67}
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 48:84:44:fd:88:e5
  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 ec:ae:d3:45:d9:c1
}

Resolve Connectivity Issues in Wired and Wireless Networks

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

Effective Solutions for Apple macOS / OSX Users

Regardless of the version of OSX/macOS you are currently using, whether it’s 10.12.3, 11.3.4, or 12.1.9, 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 invaluable, especially for teams that have embraced remote work and Work From Anywhere (WFA).

Utilizing Built-in Scripts for Assistance

A useful tool on OSX/macOS is the sudo wdutil info, which displays the current wireless settings in the CLI and can also be configured to generate specific logs for troubleshooting. Additionally, the sysdiagnose tool can be used to generate a wide range of logs, although much of it is only point-in-time related to wireless, just like 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, 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 or use Cmd+Shift+G in Finder to locate the path. Keep in mind that the file sizes are approximately 300MB.

Possibly Helpful Videos

Video	Title	Channel
	The Importance of Broadcast/Multicast Filtering in Wi-Fi HD Arjan Koopen WLPC EU Budapest 2016	Wireless LAN Professionals
	WiFiShark Fu Eddie Forero WLPC Phoenix 2019	Wireless LAN Professionals
	Securing the World's Most Dangerous Wi-Fi Network Colin Vallance WLPC Phoenix 2020	Wireless LAN Professionals
	Benefits of WPA3, Enhanced Open, and Easy Connect P. Ebbecke, P. Correll WLPC Prague 2018	Wireless LAN Professionals
	What Problem is UWB Trying to Solve with Stephen Cooper	Wireless LAN Professionals

Table 1.0 - Video Help