How Do You Support Common Wifi Internet Issues
The Functioning of Internet Addressing
When using the Internet, a Public IPv4 address such as 117.155.219.189 or an IPv6 address like 2000:3d65:ae06:ed07:61ae:6735:aa41:b6f9 may be assigned to you. You can verify this information at https://test-ipv6.com/. However, for individuals who are not tech-savvy, conveying these addresses or referencing MAC addresses like ba:e2:be:3a:52:03 can be prone to errors and become complex quite rapidly. Furthermore, this method does not provide any historical data, especially from previous issues.
Navigating the World Wide Web
In order to access a webpage such as https://keebler-ruecker.biz, the first step is to contact a DNS server to convert the host segment (keebler-ruecker) combined with the Top Level Domain (biz) of the URL, into an IP address like 44.165.180.51. Your computer and browser actually convey its type with all web requests, for example, Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_3) AppleWebKit/537.75.14 (KHTML, like Gecko) Version/7.0.3 Safari/7046A194A
Understanding the Significance of Default Gateways
Your default gateway is typically an automatically configured address via DHCP. A default gateway such as 192.168.99.239 is assigned to you (though they usually end in .1 or .254 depending on the scope size) and this is the destination to which your computer directs all of its traffic to be routed further. For IPv6, a more detailed exploration can be found here, or you can verify it 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 192.168.99.239 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:cde:82d6:7a92:6c88%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): {177.52.149.214, 169.185.220.179}
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 ba:e2:be:3a:52:03
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 12:9f:b6:da:dd:3f
}
Troubleshooting Connectivity Issues for Wired and 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.
Resolving Network Problems on Apple macOS / OSX
No matter which version of OSX/macOS you are running - whether it’s 10.12.4, 11.4.1, or 12.1.2, there are various tools available for troubleshooting network issues. However, these tools do not provide a series of correlated values over time, making it challenging to identify the root cause of the problem. This is where automated remote troubleshooting becomes invaluable, particularly for teams that embrace remote work and work from anywhere (WFA).
Using Built-in Scripts for Assistance
On OSX/macOS, the sudo wdutil info tool is incredibly useful as it provides a dump of the current wireless settings to the command line interface (CLI) and can be configured to generate specific logs for troubleshooting. In addition, the sysdiagnose tool can generate a wide range of logs, although many are only relevant to a specific point in time in relation to wireless, similar to wdutil.
To run sysdiagnose in the background and generate logs in /var/tmp/<blah>.tar.gz, use the following command: sudo nohup /usr/bin/sysdiagnose -u &. If you prefer to run it interactively, you can use the command sudo /usr/bin/sysdiagnose, but be prepared for large file sizes of about 300MB.
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