How Do You Check Common Wifi Issues

Understanding Internet Addressing

When using the Internet, you are assigned a Public IPv4 or IPv6 address. The former could look like 117.84.152.193 while the latter could be 2000:2f54:1cc8:5bcc:2c11:4c11:d110:f452. To verify your address, visit https://test-ipv6.com/. Communicating these addresses, as well as MAC addresses like c5:23:9d:8e:81:24, can be challenging for non-technical individuals. Furthermore, accessing historical data about these addresses and any associated issues can be difficult.

Navigating the World Wide Web

When you want to visit a website such as https://king.net, your computer utilizes a DNS server to translate the URL’s host (king) and Top Level Domain (net) into an IP address, like 193.185.77.209. Additionally, your computer and browser transmit their type with every web request, for example:
Opera/9.80 (X11; Linux i686; Ubuntu/14.10) Presto/2.12.388 Version/12.16

Significance of Default Gateways

Typically assigned through DHCP, your default gateway, like 192.168.238.6, is where your computer directs all its outgoing traffic. For a more in-depth look at IPv6, visit how-to-fix-ipv6-connectivity/. On Mac or Linux, you can verify this information with 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  192.168.238.6    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   fe80:2013:2f5c:86d4:4904%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): {42.210.92.35, 160.176.155.34}
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 c5:23:9d:8e:81:24
  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 43:c6:4b:77:c2:d3
}

Resolve Connectivity Issues for Wired and Wireless Networks

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

Recommended Troubleshooting Steps for Apple macOS / OSX

No matter which version of OSX/macOS is currently in use, whether it’s 10.13.4, 11.0.2, or 12.3.6, there are various tools available for troubleshooting connectivity issues. However, the manual actions and scripts available do not provide a series of correlated values over time. This is where automated remote troubleshooting becomes essential, especially for teams that operate remotely and embrace Work From Anywhere (WFA).

Useful Built-in Tools for Troubleshooting

A highly beneficial tool 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 only relevant to wireless networks, similar to wdutil.

Running sudo nohup /usr/bin/sysdiagnose -u & in the background will generate logs in /var/tmp/<blah>.tar.gz. For interactive use, you can run
sudo /usr/bin/sysdiagnose, which will display a privacy warning. If not run in the background, it should open Finder in the correct location, allowing you to navigate to /var/tmp or use Finder with Cmd+Shift+G. However, be mindful of the file sizes, which can be around 300MB.

Possibly Helpful Videos

Video	Title	Channel
	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
	IEEE 802 11kvr Perry Correll WLPC Phoenix 2019	Wireless LAN Professionals
	Wi-Fi diagnostics built into MacOS you might not be aware of	Wireless LAN Professionals
	Next Generation Troubleshooting with Meraki Wireless Devin Barger WLPC Prague 2018	Wireless LAN Professionals

Table 1.0 - Video Help