How Do You Fix Common Wifi No Access
Understanding Internet Address Assignment
When connecting to the internet, you are assigned a Public IPv4 address such as 102.49.129.252 or an IPv6 address like 2000:1c0:9d9a:8932:19de:610c:e6a1:322. These addresses can be verified using https://test-ipv6.com/. However, it can be challenging for non-technical individuals to communicate, or even remember, these addresses, as well as MAC addresses such as d0:34:bd:62:b4:97. Moreover, this method does not provide historical data, particularly when troubleshooting past issues.
Navigating the World Wide Web
Accessing a webpage, such as https://corwin-lynch.com, involves initially reaching out to a DNS server to translate the host part (corwin-lynch) combined with the Top Level Domain (com) of the URL into an IP address, for instance 103.135.120.33. Additionally, your computer and browser transmit their type along with all web requests, as shown by `Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; AS; rv:11.0) like Gecko
Significance of Default Gateways
The default gateway is typically an automatically assigned address via DHCP, such as 192.168.188.204 (although they usually end in .1 or .254 depending on the scope size). This is where your computer forwards all its traffic to be routed further. To delve deeper into IPv6 issues, refer to how-to-fix-ipv6-connectivity/. You can also verify this information on Mac or Linux platforms by following certain steps.
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 192.168.188.204 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 b3:7255:7006:8d95:b6c1:f433:d1b6:81a9%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): {232.244.211.232, 102.105.134.26}
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 d0:34:bd:62:b4:97
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 31:f0:40:03:46:74
}
Resolving Connectivity Issues for Wired and Wireless Networks
When it comes to transferring data to your router, you may be using a wired or wireless (Wi-Fi) medium at the physical and data layer.
Troubleshooting Tips for Apple macOS / OSX
Regardless of your OSX/macOS version, whether it’s 10.13.3, 11.1.3, or 12.2.6, there are various tools available for troubleshooting. However, these manual actions and scripts do not provide a series of correlated values over time. Remote troubleshooting, on the other hand, proves to be valuable, especially for teams that practice remote work and Work From Anywhere (WFA).
Utilizing the Pre-Installed Scripts
One of the useful tools 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. Furthermore, the sysdiagnose tool can be used to generate a wide range of logs, although much of it is relevant to wireless only, similar to wdutil.
Running sudo nohup /usr/bin/sysdiagnose -u & in the background will write logs to /var/tmp/<blah>.tar.gz. If you prefer to run it interactively, you can execute sudo /usr/bin/sysdiagnose, which will prompt a privacy warning. Running it in the background will open Finder in the correct location, or you can navigate to /var/tmp using Finder with Cmd+Shift+G. However, keep in mind that the file sizes are approximately 300MB.
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