How Do You Check Common Wifi No Access
Understanding Internet Addressing
When connecting to the Internet, you are assigned a Public IPv4 address such as 79.154.73.117 or an IPv6 address like 2000:48e8:fbcd:f117:4d2e:b3d1:5151:b9b. These addresses can be verified using https://test-ipv6.com/. However, for those who are not technically inclined, communicating these addresses or MAC addresses like 36:99:82:72:bb:9f can lead to errors and confusion. Furthermore, this method does not provide historical data, particularly when dealing with previous issues.
Navigating the World Wide Web
Accessing a website like https://fahey-strosin.info involves requesting the IP address, such as 105.142.102.18, associated with the host portion (fahey-strosin) and the Top Level Domain (info) of the URL from a DNS server. Your computer and browser include its type in all web requests, for example: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2228.0 Safari/537.36
The Significance of Default Gateways
The default gateway is usually an automatically assigned address through DHCP. It typically ends in .1 or .254 depending on the scope size, such as 192.0.0.245, and serves as the routing point for all traffic from your computer. For IPv6, detailed instructions are available in our how-to-fix-ipv6-connectivity/, and you can verify on Mac or Linux 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 192.0.0.245 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 fe80:4e61:4b92:9ad:d555%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): {90.112.183.153, 105.162.252.96}
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 36:99:82:72:bb:9f
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 11:c4:52:10:ea:02
}
Resolving Connectivity Issues for Wired or Wireless Networks
When it comes to transmitting data to your router, you may be using either a wired or wireless (Wi-Fi) medium at the physical and data layer.
Troubleshooting Tips for Apple macOS / OSX Systems
Regardless of whether you are running OSX/macOS versions such as 10.11.3, 11.1.3, or 12.3.9, there are various troubleshooting tools available. However, these manual actions and scripts do not provide a series of correlated values over time. This is where automated remote troubleshooting becomes valuable, especially for teams that embrace remote work and Work From Anywhere (WFA) setups.
Utilizing Built-in Scripts
A useful tool on OSX/macOS is the sudo wdutil info command, which provides a dump of the current wireless settings to the CLI and can generate specific troubleshoot logs. Additionally, the sysdiagnose tool can be used to generate a wide range of logs, although it is mostly point-in-time in relation to wireless, similar to wdutil.
Running sudo nohup /usr/bin/sysdiagnose -u & in the background will write logs to /var/tmp/<blah>.tar.gz. Alternatively, running sudo /usr/bin/sysdiagnose interactively will give a privacy warning and open Finder in the correct location, allowing you to navigate to /var/tmp or use Finder with Cmd+Shift+G to point to the path. However, be mindful of the file sizes, which are approximately 300MB.
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