How Can I Check Common Wifi Internet Issues
The Functioning of Internet Addressing
When using the Internet, you can obtain a Public IPv4 address such as 181.244.26.108 or an IPv6 address like 2000:4d33:c5b5:4b20:5a15:6082:f0d6:c2a8. This information can be verified at https://test-ipv6.com/. However, explaining these addresses to individuals who are not tech-savvy, or even providing MAC addresses like d6:83:a0:3d:25:06, can result in errors and become complex quickly. Moreover, this approach does not provide any historical data, particularly regarding previous issues.
Navigating the World Wide Web
In order to visit a website such as https://rohan.info, the initial step involves accessing a DNS server to convert the host portion (rohan) combined with the Top Level Domain (info) of the URL into an IP address like 201.125.53.231. Your computer and browser actually send their type with all web requests, for example: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_3) AppleWebKit/537.75.14 (KHTML, like Gecko) Version/7.0.3 Safari/7046A194A
Understanding the Significance of Default Gateways
The default gateway is typically an address that is automatically configured via DHCP. You receive a default gateway such as 192.0.0.109 (although they usually end in .1 or .254 depending upon the scope size) and this is where your computer directs all its traffic to be routed onwards. For manual checking on Mac or Linux, one can refer to the detailed information provided in how-to-fix-ipv6-connectivity/ for IPv6 connectivity.
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 192.0.0.109 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 fe80:7c2d:5b3f:67a3:4ed7%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): {189.68.19.129, 201.195.76.200}
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 d6:83:a0:3d:25:06
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 5e:23:76:e8:30:18
}
Ways to Resolve Issues with Wired and Wireless Connections
When it comes to sending data to your router, the physical and data layer may involve using a wired or wireless (Wi-Fi) medium.
Steps to Take on Apple macOS / OSX
No matter the version of OSX/macOS you are utilizing, whether it’s 10.15.4, 11.2.1, or 12.2.9, 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 essential, especially for teams that are embracing remote work and the concept of Work From Anywhere (WFA).
Useful Built-in Scripts
A handy tool on OSX/macOS is sudo wdutil info, which provides a dump to the CLI of current wireless related settings 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 relevant at a specific point in time, similar to the wdutil tool.
To run sysdiagnose in the background and have it write logs to /var/tmp/<blah>.tar.gz, use the command sudo nohup /usr/bin/sysdiagnose -u &. If you prefer to run it interactively, you can use the command sudo /usr/bin/sysdiagnose and it will give 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. Keep in mind that the file sizes are around 300MB give or take.
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 🏠🏝🛰.
