How Do You Troubleshoot Wifi Internet Issues

Understanding How Internet Addresses Function

When using the Internet, you may be assigned a Public IPv4 address such as 11.163.1.11 or an IPv6 address like 2000:5a08:8547:c501:a302:3038:1ef1:916a. These can be verified at https://test-ipv6.com/. However, conveying these addresses to those not well-versed in technology, or even dealing with MAC addresses like c9:b2:fa:cc:b5:6c, can easily lead to errors and complexities. Furthermore, this approach lacks historical data, especially when addressing past issues.

Navigating the World Wide Web

Accessing a website such as https://pacocha.net involves an initial connection to a DNS server, which translates the host portion (pacocha) and the Top Level Domain (net) of the URL into an IP address like 215.239.101.167. Your computer and browser also transmit their type with all web requests, for example:
Opera/9.80 (X11; Linux i686; Ubuntu/14.10) Presto/2.12.388 Version/12.16

Recognizing the Significance of Default Gateways

The default gateway is typically an automatically assigned address through DHCP. For instance, you may receive a default gateway like 172.31.45.182 (usually ending in .1 or .254 based on the scope size), which serves as the location where your computer forwards all its traffic. More detailed information on configuring IPv6 connectivity can be found at how-to-fix-ipv6-connectivity/. On Mac or Linux systems, this can be verified 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  172.31.45.182    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:b403:8035:7a5a:75f0%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): {49.204.122.211, 183.149.190.29}
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 c9:b2:fa:cc:b5:6c
  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 3a:94:b4:9b:f7:18
}

Fixing Connectivity Issues for Wired and Wireless Networks

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

Resolving Connection Problems on Apple macOS / OSX

Regardless of the version of OSX/macOS you are using, whether it’s 10.11.2, 11.4.3, or 12.2.5, there are various tools available for troubleshooting. However, these manual actions and scripts do not provide a series of correlated values over time. This is where automated remote troubleshooting becomes valuable, particularly for teams that embrace remote work and Work From Anywhere (WFA).

Using Built-in Scripts for Assistance

One extremely helpful tool on OSX/macOS is the “sudo wdutil info” command, which provides a dump of current wireless related settings to the CLI and can also be configured to generate specific logs for troubleshooting. In addition, the “sysdiagnose” tool can be used to generate a wide range of logs, although much of it is only related to wireless issues, similar to wdutil.

Running “sudo nohup /usr/bin/sysdiagnose -u &” in the background will generate logs in “/var/tmp/.tar.gz” for you. Alternatively, you can run “sudo /usr/bin/sysdiagnose” interactively, although there is not much interaction. It will give a privacy warning and when not run in the background, it should open Finder in the correct location or you can navigate to “/var/tmp” using Finder with Cmd+Shift+G. Just be aware of the file sizes, which are around 300MB more or less.

Possibly Helpful Videos

Video	Title	Channel
	WIDS/WIPS / Reseller FAQ WLPC Wireless LAN Weekly EP 14	Wireless LAN Professionals
	Automated Root Cause Analysis in Wireless Networks Karan Gupta	Wireless LAN Professionals
	Wi Fi Issues in the Wild Gopinath K.N. WLPC Phoenix 2018	Wireless LAN Professionals
	Wi-Fi diagnostics built into MacOS you might not be aware of	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