How Do You Test Wifi Router Issues
Understanding Internet Addressing
When connecting to the Internet, you are assigned a Public IPv4 address, such as 83.52.245.45, or an IPv6 address, like 2000:d655:204b:8d72:31b1:7176:fcbd:39e6. These addresses can be verified at https://test-ipv6.com/. However, communicating these addresses, including MAC addresses like 8a:60:a0:85:fd:a1, to individuals who are not tech-savvy can be error-prone and complex. Furthermore, this method does not provide any historical data, particularly in cases of past issues.
Navigating the Internet
In order to access a website, such as https://kuhlman.net, your computer initially contacts a DNS server to translate the host portion (kuhlman) combined with the Top Level Domain (net) of the URL into an IP address, such as 141.158.194.222. Additionally, your computer and browser transmit its type with all web requests, for example:
Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2228.0 Safari/537.36
The Significance of Default Gateways
In most cases, your default gateway is automatically configured via DHCP and assigned an address, such as 10.162.98.61 (commonly ending in .1 or .254 based on the scope size). This is the location where your computer sends all its traffic to be routed onwards. For IPv6, a detailed guide is available at how-to-fix-ipv6-connectivity/. On Mac or Linux, you can verify this using the following commands:
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 10.162.98.61 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 fe80:81db:c6a4:96e4:94cd%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): {115.76.150.194, 121.40.140.178}
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 8a:60:a0:85:fd:a1
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 70:39:5a:97:14:0d
}
Solutions for Dealing with Wired or Wireless Issues
When it comes to transmitting data at the physical and data layer, you may encounter problems with your wired or wireless (Wi-Fi) connection to your router.
Troubleshooting Strategies for Apple macOS / OSX
Regardless of which version of OSX or macOS you are using, whether it’s 10.14.8, 11.4.4, or 12.1.1, there are various tools available for troubleshooting. However, the manual actions and scripts provided may not offer a consistent set of correlated values over time. This is where automated remote troubleshooting becomes valuable, especially for teams that embrace remote work and Work From Anywhere (WFA).
Utilizing Built-in Scripts for Assistance
One tool that can be very 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 logs for troubleshooting. Another tool, the sysdiagnose tool, offers a more comprehensive option for generating a wide range of logs, although much of it is only point-in-time data in relation to wireless, similar to wdutil.
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 &. Alternatively, for an interactive but not very interactive experience, you can run sudo /usr/bin/sysdiagnose and it will display 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. Be mindful of the file sizes, which are typically 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 🏠🏝🛰.
