How To Support Wifi Internet Issues
Understanding Internet Addressing
When using the Internet, your device may be assigned a Public IPv4 address such as 57.216.149.224 or an IPv6 address like 2000:87fc:ce99:9c70:450:bf96:c112:911d. This information can be verified at https://test-ipv6.com/. However, for those who are not well-versed in technical jargon, attempting to communicate these addresses or even MAC addresses like 8b:44:8b:b7:55:d4 can be prone to error and become an intricate task. Furthermore, this does not provide any historical data about past issues.
Navigating the World Wide Web
When attempting to access a website such as https://morar.biz, the first step involves reaching out to a DNS server in order to convert the host portion (morar) along with the Top Level Domain (biz) of the URL into an IP address, like 85.217.237.156. Your computer and browser include specific details with every web request, such as Mozilla/5.0 (Windows NT x.y; Win64; x64; rv:10.0) Gecko/20100101 Firefox/10.0
The Significance of Default Gateways
The default gateway is typically an address that is automatically configured via DHCP. This address, such as 192.168.19.222 (although it usually ends in either .1 or .254 depending on the scope size), serves as the point to which your computer directs all its traffic for further routing. For IPv6, detailed instructions can be found at how-to-fix-ipv6-connectivity/, and on Mac or Linux systems, this can be verified 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 192.168.19.222 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 fe80:13fb:79bf:1c24:abdf%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): {2.41.182.49, 111.238.162.246}
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 8b:44:8b:b7:55:d4
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 47:a2:fe:8c:0d:ff
}
Resolve Issues with Wired and Wireless Connections
When it comes to transmitting data to your router, you might be using a wired or wireless (Wi-Fi) medium at the physical and data layer.
Guidelines for Apple macOS / OSX Users
Regardless of whether you are running 10.14.4, 11.6.4, or 12.0.2, 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).
Utilize Integrated Scripts for Assistance
One of the useful tools on OSX/macOS is the sudo wdutil info, which provides a dump of current wireless-related settings to the CLI and can also be configured to generate specific logs for troubleshooting. Additionally, the sysdiagnose tool can be used to generate a wide range of logs, although much of it is only relevant to wireless at a specific point in time, similar to wdutil.
Running sudo nohup /usr/bin/sysdiagnose -u & in the background will write logs to /var/tmp/<blah>.tar.gz for you. If you prefer to run it interactively, you can use sudo /usr/bin/sysdiagnose, which will provide a privacy warning. When not run in the background, it should open Finder in the correct location, or you can navigate to /var/tmp using Finder with Cmd+Shift+G. However, be cautious of the file sizes, which are around 300MB.
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