How Do You Test Common Wifi Issues

Understanding Internet Addressing When you’re using the Internet, you will be assigned a Public IPv4 address such as 174.61.185.2 or an IPv6 address like 2000:8:f5b2:7342:ad81:79cd:601e:4677. You can verify this information by visiting https://test-ipv6.com/. However, for those who are not well-versed in technology, communicating these addresses or even mentioning MAC addresses like 4f:97:25:30:6c:b9 can become error-prone and overly complex. Understanding Internet Addressing When you’re using the Internet, you will be assigned a Public IPv4 address such as 174.61.185.2 or an IPv6 address like 2000:8:f5b2:7342:ad81:79cd:601e:4677. You can verify this information by visiting https://test-ipv6.com/. However, for those who are not well-versed in technology, communicating these addresses or even mentioning MAC addresses like 4f:97:25:30:6c:b9 can become error-prone and overly complex.

Understanding Internet Addressing

When you’re using the Internet, you will be assigned a Public IPv4 address such as 174.61.185.2 or an IPv6 address like 2000:8:f5b2:7342:ad81:79cd:601e:4677. You can verify this information by visiting https://test-ipv6.com/. However, for those who are not well-versed in technology, communicating these addresses or even mentioning MAC addresses like 4f:97:25:30:6c:b9 can become error-prone and overly complex. Furthermore, it doesn’t provide any historical data, especially from previous incidents.

When trying to access a webpage like https://mosciski.info, the first step is to connect to a DNS server in order to translate the host portion (mosciski) combined with the Top Level Domain (info) of the URL into an IP address such as 149.145.246.31. As your computer and browser transmit basic information with each web request, for example:
Mozilla/5.0 (Windows; U; Win 9x 4.90; SG; rv:1.9.2.4) Gecko/20101104 Netscape/9.1.0285

The Significance of Default Gateways

Typically, your default gateway is assigned through DHCP and is usually an automatically configured address like 10.176.158.163 (although they generally end in .1 or .254 depending on the size of the scope). This is where your computer directs all of its traffic to be routed onward. For more information on IPv6, you can delve into how-to-fix-ipv6-connectivity/, or check on Mac or Linux using 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  10.176.158.163    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   fe80:5f4:290b:fbf9:bf5a%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): {131.119.122.150, 122.22.198.15}
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 4f:97:25:30:6c:b9
  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 a0:48:f2:8f:0a:fa
}

Fixing Connectivity Issues in Wired and Wireless Networks

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

Troubleshooting Tips for Apple macOS / OSX Users

Regardless of whether you are working on OSX/macOS version 10.13.8, 11.4.7, or 12.0.7, there are various tools available for troubleshooting. However, these manual actions and scripts do not provide a set of correlated values over time. This is where automated remote troubleshooting becomes invaluable, particularly for teams that embrace remote work and Work From Anywhere (WFA).

Internal Scripts for Assistance

An extremely useful tool on OSX/macOS is the sudo wdutil info command, 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 produce a wide range of logs, although many are only relevant to wireless in the present moment, much like the wdutil.

To run it in the background and generate logs, you can use the command sudo nohup /usr/bin/sysdiagnose -u &, which will write the logs to /var/tmp/<blah>.tar.gz. If you prefer to run it interactively, you can use the command
sudo /usr/bin/sysdiagnose, which will trigger 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 mindful of the file sizes, which are approximately 300MB, more or less.

Possibly Helpful Videos

Video Title Channel
Wireless Association & Authentication Pass-Fail Brian Long WLPC US Phoenix 2017 Wireless LAN Professionals
Securing the World's Most Dangerous Wi-Fi Network Colin Vallance WLPC Phoenix 2020 Wireless LAN Professionals
TIP OpenWifi Demo Network Setup for WLPC Drew Lentz WLPC Prague 2022 Wireless LAN Professionals
Real World Protocol Analysis Peter Mackenzie WLPC_EU Lisbon 2017 Wireless LAN Professionals
The Importance of Broadcast/Multicast Filtering in Wi-Fi HD Arjan Koopen WLPC EU Budapest 2016 Wireless LAN Professionals
Table 1.0 - Video Help



P.S. PanSift Tip For Work From Anywhere Support

Digital work requires reliable connectivity for voice, video, and data. Inevitable Wi-Fi, network, and system issues cause teams to lose time and productivity, or worse, to miss out on opportunities. Whether working from home, a shared space, or an office, and irrespective of the network being managed or unmanaged, forward thinking technical teams embrace smarter tools to save their users and clients time and money! See how PanSift provides instant remote troubleshooting, irrespective of location 🏠🏝🛰.

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