How Can I Fix Wifi Internet Issues
The Functioning of Internet Addressing
When using the Internet, individuals may have a Public IPv4 address, which could be something like 92.75.110.206, or an IPv6 address, such as 2000:5cd3:c2a9:5dfa:85e1:27c8:e38:6edf. This can be verified using https://test-ipv6.com/. However, when attempting to communicate these addresses to those who are not technologically inclined, or even referencing MAC addresses like 2f:a5:27:79:f6:98, errors can easily occur and things can get complicated fast. Moreover, this does not provide any historical data, particularly when past issues have arisen.
Navigating the World Wide Web
In order to access a website, such as https://fisher.com, one first reaches a DNS server to convert the host section (fisher) in conjunction with the URL’s Top Level Domain (com), into an IP address, for instance 144.20.139.52. With every web request, your computer and browser actually transmit its type, such as Mozilla/5.0 (Windows NT x.y; Win64; x64; rv:10.0) Gecko/20100101 Firefox/10.0
Understanding the Significance of Default Gateways
Typically, the default gateway is an automatically configured address via DHCP. This is where your computer sends all its traffic to be routed onwards, and you will often receive a default gateway like 192.0.0.153 (although they generally end in .1 or .254, depending on the scope size). There is an in-depth guide on how-to-fix-ipv6-connectivity/ for IPv6, but on Mac or Linux, you can check by:
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 192.0.0.153 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 fe80:6b47:24c2:3042:ffc7%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): {188.42.27.82, 57.134.46.206}
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 2f:a5:27:79:f6:98
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 9a:b3:c8:fa:eb:1f
}
Troubleshooting Issues with Wired and Wireless Connections
When it comes to the physical and data layer, there are various ways to send data to your router, including using a wired or wireless (Wi-Fi) medium.
Tips for Resolving Problems on Apple macOS / OSX
Regardless of which version of OSX/macOS you have, whether it’s 10.15.9, 11.4.4, or 12.2.1, there are multiple tools available for troubleshooting. However, these manual actions and scripts do not provide a set of correlated values over time. This is where automated remote troubleshooting proves to be particularly useful, especially for teams that are working remotely and embracing the concept of Work From Anywhere (WFA).
Utility Scripts Available
One useful tool on OSX/macOS is sudo wdutil info, which provides a dump of the current wireless settings to the CLI, and can also be configured to generate specific logs for troubleshooting purposes. Additionally, the sysdiagnose tool can be used to generate a wide range of logs, although many are only related to the wireless settings, similar to wdutil.
Running sudo nohup /usr/bin/sysdiagnose -u & in the background will generate logs in /var/tmp/<blah>.tar.gz. If you prefer to run it interactively, you can use sudo /usr/bin/sysdiagnose, but be aware that the file sizes can be around 300MB.
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