How To Support Common Wifi No Access
Explanation of Internet Addressing
When using the Internet, you are assigned a Public IPv4 address, such as 88.248.113.97, or an IPv6 address like 2000:1678:c333:4637:5429:3b9b:187:4e13. You can verify this information by visiting https://test-ipv6.com/. It can be challenging for those without a technical background to communicate these addresses accurately or identify MAC addresses like 74:df:d1:b5:f1:33, which can create complications. Furthermore, this method does not provide any historical data, particularly in cases of past issues.
How to Access Websites
In order to reach a website, such as https://beatty-hilll.net, your computer connects to a DNS server to convert the host name (beatty-hilll) along with the Top Level Domain (net) of the URL into an IP address, such as 5.176.62.93. When making web requests, your computer and browser transmit their type, for example: Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; AS; rv:11.0) like Gecko
Significance of Default Gateways
Your default gateway is typically assigned automatically through DHCP. It will be a default gateway like 10.119.234.45 (although they often end in .1 or .254 based on the size of the scope) and it is responsible for routing all your computer’s traffic. For IPv6 connectivity, detailed instructions can be found at how-to-fix-ipv6-connectivity/, or on Mac and Linux systems 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 10.119.234.45 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:a936:c8ee:59c9:e9e4%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): {10.215.65.220, 240.51.191.173}
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 74:df:d1:b5:f1:33
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 b4:bf:7e:02:ed:37
}
Resolve Connectivity Issues for Wired and Wireless Networks
When it comes to sending data to your router, you may utilize either a wired or wireless (Wi-Fi) medium at the physical and data layer.
Troubleshooting Solutions for Apple macOS / OSX
Regardless of the version of OSX/macOS you are using, whether it’s 10.11.8, 11.4.1, or 12.3.2, there are various tools available for resolving connectivity issues. However, these manual actions and scripts fail to provide a set of correlated values over time. This is where automated remote troubleshooting becomes valuable, particularly for teams that have embraced remote work and Work From Anywhere (WFA).
Useful Built-in Commands for Troubleshooting
One useful tool on OSX/macOS is the sudo wdutil info command, which provides a dump of the current wireless settings to the CLI, and can also be configured to generate specific logs for troubleshooting. Another comprehensive tool is the sysdiagnose command, which can generate a wide range of logs (although many are only relevant to wireless settings at a specific point in time, similar to wdutil).
To run the sysdiagnose command in the background and write logs to /var/tmp/<blah>.tar.gz, you can use the command sudo nohup /usr/bin/sysdiagnose -u &. If you prefer to run it interactively (even though there is minimal interaction), you can use the command sudo /usr/bin/sysdiagnose, which 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 or use Finder with Cmd+Shift+G to locate the path. Keep in mind that the file sizes are approximately 300MB.
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