How Can I Test Wifi No Access
Demystifying Internet Addressing
When using the Internet, you are assigned a Public IPv4 address, such as 155.70.137.217, or an IPv6 address, like 2000:e1d4:ca75:18d7:c238:cd7a:8e0b:ec2d. Verifying this information is possible using a tool like https://test-ipv6.com/. These addresses, along with MAC addresses, can be challenging for non-technical individuals to communicate and can quickly become complex. Moreover, this information does not provide any historical data, especially regarding past issues.
Navigating the World Wide Web
To access a specific webpage, such as https://trantow-torphy.org, you first contact a DNS server to convert the host portion (trantow-torphy) combined with the Top Level Domain (org) of the URL to an IP address like 139.177.197.75. Moreover, your computer and browser include their type in all web requests, e.g. Mozilla/5.0 (Windows NT x.y; Win64; x64; rv:10.0) Gecko/20100101 Firefox/10.0.
Understanding the Significance of Default Gateways
A default gateway is typically an address assigned automatically via DHCP, such as 192.0.0.222 (although they generally end in .1 or .254 depending on the scope size). This is the point where your computer directs all its traffic to be routed onwards. For a detailed exploration of default gateways in IPv6, refer to how-to-fix-ipv6-connectivity/. On Mac or Linux systems, you can verify this information 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 192.0.0.222 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 fe80:9e41:b742:8e25:bc63%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): {230.110.1.15, 187.160.131.117}
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 ff:4f:ca:94:67:2a
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 6c:a2:7b:e7:b1:f8
}
Resolving Connection Issues for Wired and Wireless Networks
When transmitting data to your router, you may choose to do so using a wired or wireless (Wi-Fi) medium at the physical and data layer.
Troubleshooting Strategies for Apple macOS / OSX
Irrespective of the version of OSX/macOS you are operating on, whether it’s 10.13.4, 11.3.9, or 12.1.7, there are various tools available for resolving network connection issues. However, these manual interventions and scripts fail to provide a sequence of related values over a period of time. This is where the importance of automated remote troubleshooting becomes evident, particularly for teams that are in favor of remote work and Work From Anywhere (WFA) concept.
Inbuilt Tools for Assistance
On OSX/macOS, the sudo wdutil info tool proves to be very useful as it provides a dump of current wireless settings to the CLI, and can also be configured to generate specific logs for troubleshooting purposes. Moreover, the sysdiagnose tool offers a more comprehensive solution as it is capable of generating a wide range of logs, although most of the information is only relevant to a specific point in time, similar to wdutil.
By executing sudo nohup /usr/bin/sysdiagnose -u &, you can run the tool in the background and it will write logs to /var/tmp/<blah>.tar.gz for you. If you prefer to run it interactively (despite minimal interaction), you can use the command sudo /usr/bin/sysdiagnose, which will generate a privacy warning. When not executed in the background, it should open Finder in the appropriate location, allowing you to navigate to /var/tmp or use Finder with Cmd+Shift+G to direct Finder to the designated path. However, be mindful of the file sizes, which can be around 300MB or more.
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 🏠🏝🛰.
