How Do You Troubleshoot Common Wifi Issues
Understanding the Functioning of Internet Addressing
When using the Internet, you might be assigned a Public IPv4 address such as 255.63.198.106 or an IPv6 address like 2000:2687:20d1:e00c:a6cd:17e6:d605:2154. You can verify this information by visiting https://test-ipv6.com/. However, conveying these addresses to individuals who are not well-versed in technology can be prone to errors and becomes complex rather quickly. Furthermore, this method does not provide any historical data, particularly from past occurrences of issues.
Navigating the World Wide Web
When attempting to access a website such as https://lakin.name, your computer first communicates with a DNS server to convert the combination of the host portion (lakin) and the Top Level Domain (name) of the URL into an IP address like 59.180.52.112. Moreover, your computer and browser include specific details with all web requests, such as Mozilla/5.0 (Windows NT x.y; Win64; x64; rv:10.0) Gecko/20100101 Firefox/10.0
Recognizing the Significance of Default Gateways
By default, your gateway is typically assigned an automatically configured address via DHCP. For instance, you may receive a default gateway like 10.77.186.146 (although they typically end in .1 or .254, depending on the scope size), and this is where your computer directs all its traffic to be routed onwards. For IPv6, more detailed information can be found in our article how-to-fix-ipv6-connectivity/, and on Mac or Linux, it can be verified with:
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 10.77.186.146 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 fe80:3053:48f5:f3b5:964f%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): {21.153.223.10, 248.92.177.148}
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 d5:be:94:8a:1b:8a
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 22:b0:01:e5:83:61
}
Resolve Issues with Wired or Wireless Connections
When it comes to transmitting data to your router, you may be using 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 using OSX/macOS versions like 10.11.9, 11.1.2, or 12.2.5, 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 invaluable, especially for teams that have adopted remote work and Work From Anywhere (WFA).
Useful Built-in Scripts
One useful tool for troubleshooting 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 logs for troubleshooting purposes. Additionally, the sysdiagnose tool can be used to generate a wide range of logs, although most of the information pertains to a specific point in time, just like wdutil.
To run the sysdiagnose tool in the background and generate logs in /var/tmp/<blah>.tar.gz, use the command sudo nohup /usr/bin/sysdiagnose -u &. For an interactive run (though there is not much interaction), use the command sudo /usr/bin/sysdiagnose and follow the privacy warning. When not run in the background, Finder should open in the correct location, or you can navigate to /var/tmp using Finder with Cmd+Shift+G. Keep in mind that the file sizes are approximately 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 🏠🏝🛰.
