How Can I Fix Wifi No Access
Explanation of Internet Addressing
When surfing the web, you might encounter a Public IPv4 address such as 87.15.133.160 or an IPv6 address like 2000:65f8:c65c:ff26:b65d:7ab9:e572:ccfa. This can be confirmed by visiting https://test-ipv6.com/. However, expressing these addresses, or even mentioning MAC addresses like 1b:a7:eb:d4:1a:58 to those less knowledgeable in technology can be prone to errors and become complex. Furthermore, this method does not provide any historical data, especially when previous issues have arisen.
Navigating the World Wide Web
Accessing a website such as https://steuber-rempel.biz involves interaction with a DNS server to translate the host portion (steuber-rempel) along with the Top Level Domain (biz) of the URL, into an IP address like 244.229.85.237. Whenever you make web requests, your computer and browser sends its type, such as Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; AS; rv:11.0) like Gecko
Significance of Default Gateway Configuration
The default gateway typically obtains its address through automatic configuration via DHCP. It usually ends with .1 or .254, depending on the scope size, such as 172.21.168.59. This is the destination to which your computer directs all outgoing traffic to be routed. For IPv6, detailed instructions can be found in how-to-fix-ipv6-connectivity/ but can be verified on Mac or Linux 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 172.21.168.59 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 fe80:5b42:165d:145d:9914%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): {82.80.194.96, 56.111.139.185}
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 1b:a7:eb:d4:1a:58
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 e2:52:48:49:cd:4e
}
Resolving Connectivity Issues on Wired and Wireless Networks
In order to transmit data to your router, you may be utilizing a wired or wireless (Wi-Fi) connection at the physical and data layer.
Troubleshooting Methods for Apple macOS / OSX
No matter which version of OSX/macOS you are operating on, such as 10.15.9, 11.1.7, or 12.2.3, there is a variety of tools available for resolving connectivity issues. However, these manual interventions and scripts do not provide a series of correlated values over time. This is where automated remote troubleshooting becomes crucial, especially for teams engaging in remote work and Work From Anywhere (WFA).
Utilizing Pre-Installed Scripts
One useful tool on OSX/macOS is the sudo wdutil info, which produces a dump of current wireless settings in the CLI and can also be set up to create specific logs for troubleshooting. Furthermore, the sysdiagnose tool can generate a comprehensive range of logs (although much of it is only relevant to wireless settings, 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 (even though there is minimal interaction), you can execute sudo /usr/bin/sysdiagnose, which will prompt a privacy warning. When not run in the background, it should open Finder in the appropriate location, or you can navigate to /var/tmp using Finder with Cmd+Shift+G. However, be cautious of the file sizes, which are approximately 300MB.
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