How Do You Support Common Wifi Connectivity

Explanation of Internet Protocol Addressing

When using the Internet, you are assigned an IP address, such as 61.223.206.140 for IPv4 or 2000:d847:f1bb:c7a:45f0:1b3:c989:5d1a for IPv6. You can verify your IP address at https://test-ipv6.com/. However, explaining these addresses, as well as MAC addresses like 1b:a5:74:29:27:5f, to those who are not tech-savvy can lead to errors and confusion. Furthermore, this method does not provide historical data, especially when trying to resolve past issues.

Navigating the World Wide Web

To access a website, such as https://runte.biz, your device connects to a DNS server to convert the URL’s host portion (runte) and its Top Level Domain (biz) into an IP address, such as 219.243.17.196. Whenever a web request is made, your computer and browser send their specifications, such as
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_3) AppleWebKit/537.75.14 (KHTML, like Gecko) Version/7.0.3 Safari/7046A194A.

Significance of Default Gateways

By default, your gateway is usually assigned through DHCP and may appear as 192.168.198.142 (typically ending in .1 or .254, depending on the scope size). This is the point to which your computer sends all outgoing traffic to be routed further. To troubleshoot IPv6 connectivity on Mac or Linux, refer to our detailed guide how-to-fix-ipv6-connectivity/.

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  192.168.198.142    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   fe80:1efc:9273:1550:cbd3%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): {202.131.10.121, 135.50.120.166}
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:a5:74:29:27:5f
  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 03:85:92:7e:5a:99
}

Resolving Issues with Wired and Wireless Connectivity

Regardless of whether you are using a wired or wireless (Wi-Fi) connection at the physical and data layer, it is important to troubleshoot any issues in order to ensure smooth data transmission to your router.

Effective Measures for Apple macOS / OSX Users

Regardless of the version of OSX/macOS being used, whether it is 10.13.9, 11.0.8, or 12.3.8, there are various troubleshooting tools available. However, these manual actions and scripts do not provide a comprehensive set of correlated values over time. This is where automated remote troubleshooting becomes crucial, especially for remote work and Work From Anywhere (WFA) teams.

Utilizing Pre-Installed Scripts

An incredibly useful tool on OSX/macOS is the sudo wdutil info command, which provides a dump of current wireless settings to the CLI and can be configured to generate specific troubleshooting logs. Furthermore, the sysdiagnose tool can be used to generate a wide range of logs, although many are 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 (despite minimal interaction), you can run
sudo /usr/bin/sysdiagnose which will prompt a privacy warning. When not run in the background, it should open Finder in the correct location, or you can navigate to /var/tmp or use Finder with Cmd+Shift+G to locate the path. However, keep in mind that the file sizes are approximately 300MB.

Possibly Helpful Videos

Video	Title	Channel
	Next Generation Troubleshooting with Meraki Wireless Devin Barger WLPC Prague 2018	Wireless LAN Professionals
	Wireless Packet Captures with Multiple Adapters Yer Yang WLPC Phoenix 2019	Wireless LAN Professionals
	Automated Root Cause Analysis in Wireless Networks Karan Gupta	Wireless LAN Professionals
	Benefits of WPA3, Enhanced Open, and Easy Connect P. Ebbecke, P. Correll WLPC Prague 2018	Wireless LAN Professionals
	The Importance of Broadcast/Multicast Filtering in Wi-Fi HD Arjan Koopen WLPC EU Budapest 2016	Wireless LAN Professionals

Table 1.0 - Video Help