How To Support Wifi Issues
Understanding Internet Addressing
When using the Internet, you are assigned either a Public IPv4 or IPv6 address, such as 247.107.57.26 or 2000:be33:d089:bf28:971f:ec3d:f595:813f. These addresses can be verified on https://test-ipv6.com/. However, for those who are not well-versed in technology, communicating these addresses, or even mentioning MAC addresses like f1:b1:71:c7:61:e6, can quickly become prone to errors and complications. Furthermore, this does not provide any historical data, especially during previous issues.
Navigating the World Wide Web
When attempting to access a website such as https://cormier-vandervort.io, your first step involves reaching out to a DNS server to translate the host portion (cormier-vandervort) along with the Top Level Domain (io) of the URL into an IP address, like 26.171.246.44. Every web request from your computer and browser includes its type, for example: Mozilla/5.0 (Windows; U; Win 9x 4.90; SG; rv:1.9.2.4) Gecko/20101104 Netscape/9.1.0285
Understanding the Significance of Default Gateways
The default gateway is typically an automatically assigned address via DHCP, such as 192.168.218.133 (although they typically end in .1 or .254 depending on the scope size). This is where your computer sends all of its traffic to be routed onwards. For IPv6, you can refer to a detailed exploration on how-to-fix-ipv6-connectivity/. Additionally, on Mac or Linux, you can check this 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 192.168.218.133 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 fe80:4ca7:189d:74f8:6084%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): {55.248.73.111, 20.10.104.217}
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 f1:b1:71:c7:61:e6
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 66:f8:ec:34:1c:14
}
Resolving Issues with Wired and Wireless Connections
When it comes to transferring data to your router, you may be using either a wired or wireless (Wi-Fi) medium at the physical and data layer.
Troubleshooting Solutions for Apple macOS / OSX
No matter which version of OSX/macOS you’re running - whether it’s 10.12.9, 11.0.6, or 12.0.1 - there are various tools available for resolving issues. However, these manual actions and scripts do not provide a series of correlated values over time. This is where automated remote troubleshooting becomes essential, especially for teams that are adapting to remote work and embracing the concept of Work From Anywhere (WFA).
Utilizing Built-in Scripts for Assistance
A tool that can be incredibly useful on OSX/macOS is sudo wdutil info, which provides a dump of current wireless settings to the CLI, and can also be configured to generate specific troubleshooting logs. Furthermore, the sysdiagnose tool offers a more comprehensive approach, generating a wide range of logs (although many are point-in-time only in relation to wireless, similar to wdutil).
Running sudo nohup /usr/bin/sysdiagnose -u & in the background will generate logs in /var/tmp/<blah>.tar.gz. If you prefer to run it interactively (even though there’s not much interaction), you can execute sudo /usr/bin/sysdiagnose, which will provide a privacy warning. 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. However, be cautious of the file sizes, which are generally around 300MB.
Possibly Helpful Videos
P.S. Tips For Remote Network and Client Support
Digital work requires reliable connectivity. Whether for low latency or regular data streams, Wi-Fi, DNS, and network issues cause teams to lose time and productivity. Even worse is when support teams waste time trying to recreate and isolate issues! See how PanSift saves time, money, and frustration on all sides with instant remote troubleshooting 🏠🏝🛰.
