How Do You Check Common Wifi Connectivity
Understanding Internet Addressing
When it comes to the internet, you are assigned a Public IPv4 address such as 82.210.209.130 or an IPv6 address like 2000:857c:7a6b:d1de:eb9c:c387:404a:90de. You can verify this by visiting https://test-ipv6.com/. However, communicating these addresses, or even referencing MAC addresses like 87:6c:36:2a:cd:2c, can be challenging for those unfamiliar with the technical aspects. Furthermore, this method does not provide any historical data, especially regarding past issues.
Navigating the World Wide Web
When attempting to access a web page such as https://walker-conroy.com, your computer first contacts a DNS server to translate the host portion (walker-conroy) in combination with the Top Level Domain (com) of the URL into an IP address like 20.137.236.207. Each web request from your computer and browser includes detailed information, for example: Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; AS; rv:11.0) like Gecko
The Significance of Default Gateways
Your default gateway is typically assigned automatically through DHCP and may appear as an address like 10.10.192.255 (though they usually end in .1 or .254 depending on the scope size). This is where your computer directs all its traffic to be routed onwards. We offer detailed instructions for checking the default gateway on Mac or Linux in our blog post: how-to-fix-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 10.10.192.255 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:feb4:a771:7fc9:706d%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): {203.138.110.138, 35.63.15.112}
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 87:6c:36:2a:cd:2c
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 ac:e1:84:fb:93:44
}
Fixing Connectivity Issues with Wired and Wireless Network
When transferring data to your router, it’s important to troubleshoot any issues that may arise with both wired and wireless (Wi-Fi) connections at the physical and data layer.
Steps to Resolve Network Problems on Apple macOS / OSX
Regardless of the version of OSX/macOS you are using, whether it’s 10.14.5, 11.5.5, or 12.0.8, there are various tools available for troubleshooting network connectivity. However, these tools often lack the ability to provide continuous correlated values over time. This is where automated remote troubleshooting becomes invaluable, particularly for teams that operate in a remote or Work From Anywhere (WFA) environment.
Utilizing Built-in Scripts for Assistance
One useful tool on OSX/macOS is the sudo wdutil info command, which provides a detailed output of current wireless settings through the CLI. This command can also be configured to generate specific logs for troubleshooting purposes. Moreover, the sysdiagnose tool offers a more comprehensive approach, producing a wide range of logs, although many are only relevant to a specific point in time, similar to wdutil.
To run sysdiagnose in the background and generate logs in /var/tmp/<blah>.tar.gz, use the command sudo nohup /usr/bin/sysdiagnose -u &. For an interactive (albeit minimal interaction) experience, use the command sudo /usr/bin/sysdiagnose and follow the prompts. Be mindful of the large file sizes, typically around 300MB.
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