How Can I Fix Wifi Connectivity
Understanding Internet Addressing
When using the Internet, your device will be assigned a unique IPv4 or IPv6 address, such as 195.104.101.75 or 2000:8574:5eb3:10ff:27d4:5fa5:6e12:ba3f. These addresses can be verified at https://test-ipv6.com/. However, sharing and communicating these addresses, along with MAC addresses like 45:4f:03:9e:42:66, can be complex and error-prone, especially for those who are not tech-savvy. Moreover, these addresses do not provide any historical data, especially in identifying past issues.
Navigating the World Wide Web
When accessing a website, such as https://kub.org, your device communicates with a DNS server to translate the URL’s host name and Top Level Domain (TLD) to an IP address, like 43.106.34.7. Additionally, whenever your computer and browser accesses a webpage, it sends its user agent data, for example: Mozilla/5.0 (Windows NT x.y; Win64; x64; rv:10.0) Gecko/20100101 Firefox/10.0
Understanding Default Gateways
The default gateway for your device is typically automatically assigned through DHCP, usually in the form of an address like 10.46.104.89, often ending in .1 or .254 based on the scope size. This is the point to which your computer sends all its outgoing network traffic to be routed to its final destination. For in-depth guidance on IPv6 connectivity, you can refer to our article how-to-fix-ipv6-connectivity/. Additionally, on Mac or Linux systems, you can verify the default gateway 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 10.46.104.89 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:a7e7:395e:29ac:6550%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): {61.132.153.83, 206.7.255.219}
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 45:4f:03:9e:42:66
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 ca:0f:cf:69:ec:ed
}
Fixing Connectivity Issues for Wired and Wireless Networks
When it comes to the physical and data layer, you might be utilizing either a wired or wireless (Wi-Fi) medium to transmit data to your router.
Solutions for Apple macOS / OSX Users
Regardless of which version of OSX/macOS you are using, whether it’s 10.11.4, 11.4.3, or 12.1.6, there are various troubleshooting tools available. However, these manual methods and scripts do not provide a set of correlated values over time. This is where automated remote troubleshooting becomes valuable, especially for teams that are transitioning to remote work and embracing Work From Anywhere (WFA).
Helpful Built-in Scripts
One exceptionally useful tool on OSX/macOS is the 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. Furthermore, the sysdiagnose tool can be used to generate a wide range of logs (although much of it is specific to the current moment in relation to wireless, just like wdutil).
Running sudo nohup /usr/bin/sysdiagnose -u & will execute it in the background and write logs to /var/tmp/<blah>.tar.gz for you. If you prefer to run it interactively (although there isn’t much interaction), you can run sudo /usr/bin/sysdiagnose and it will issue 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. Just keep in mind that the file sizes are approximately 300MB.
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