Test Common Wifi Router Issues
Understanding Internet Addressing
When using the Internet, you will receive a Public IPv4 address such as 141.234.222.11 or an IPv6 address like 2000:a747:d47e:7def:1356:28a1:b9f7:a86e. You can verify this information at https://test-ipv6.com/. However, for individuals without technical expertise, relaying these addresses or MAC addresses like 51:b5:7c:9c:fe:9a can be prone to errors and become complex. Furthermore, this does not provide historical data, especially concerning past issues.
Navigating the World Wide Web
In order to access a website such as https://thompson.org, your device first communicates with a DNS server to convert the host component (thompson) along with the Top Level Domain (org) of the URL into an IP address, like 140.14.175.184. Your computer and browser also disclose their type with each web request e.g. Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; AS; rv:11.0) like Gecko
The Significance of Default Gateways
The default gateway is typically an automatically assigned address through DHCP. A default gateway looks like 192.168.20.230 (although they usually end in .1 or .254 based on the scope size) and serves as the point where your computer forwards all its traffic to be routed. To learn more about IPv6, you can refer to our in-depth guide on how-to-fix-ipv6-connectivity/, or you can verify using Mac or Linux 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 192.168.20.230 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 db1c:f547:9f:635f:95a1:36e2:9cb0:9421%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): {119.51.16.250, 30.192.16.183}
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 51:b5:7c:9c:fe:9a
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 5b:46:5a:68:c7:f2
}
Resolving Issues with Wired and Wireless Connections
When transferring data to your router, you may be utilizing a wired or wireless (Wi-Fi) medium at the physical and data layer.
Effective Solutions for Apple macOS / OSX
Regardless of the version of OSX/macOS you are currently using, whether it’s 10.11.4, 11.0.5, or 12.2.6, 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 invaluable, particularly for teams embracing remote work and Work From Anywhere (WFA).
Helpful Built-in Scripts
One incredibly useful tool for OSX/macOS is sudo wdutil info, which provides a dump of the current wireless settings to the CLI, and can be configured to generate specific logs for troubleshooting. Additionally, the sysdiagnose tool can be used to generate a wide range of logs, although much of it is point-in-time only in relation to wireless, similar to wdutil.
To run sysdiagnose in the background and 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 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 mindful of the file sizes, which are approximately 300MB.
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