When using the Internet, you are assigned a Public IPv4 address such as 129.165.104.25
or an IPv6 address like 2000:f7cd:1207:52cd:b777:826c:6398:d5ab
. You can verify this using https://test-ipv6.com/. However, explaining and communicating these addresses, or even referencing MAC addresses such as 51:c9:3e:bd:f5:7c
, can be prone to errors and become complex. In addition, this method lacks historical data (especially when trying to resolve past issues).
To access a webpage like https://hickle.net, you first connect to a DNS server to translate the host part (hickle) along with the Top Level Domain (net) of the URL to an IP address such as 125.246.205.241
. Your computer and browser send specific information with each web request, for example:
Mozilla/5.0 (compatible; MSIE 9.0; AOL 9.7; AOLBuild 4343.19; Windows NT 6.1; WOW64; Trident/5.0; FunWebProducts)
The default gateway is typically an address that is automatically assigned via DHCP. You will receive a default gateway like 172.21.92.6
(usually ending in .1 or .254 depending on the scope size), and this is the point where your computer sends all its traffic to be routed onward. For IPv6
, you can find more detailed information on how-to-fix-ipv6-connectivity/, but on Mac or Linux, you can check with:
ip -6 route```
### IPv4 Routes and the Host IPv4 Route Table (inc. VPN)
```netstat -rn -f inet | egrep -i "default|0/1|128.0/1"```
<pre>
0/1 172.18.12.193 UGScg utun3
default 172.21.92.6 UGScg en0
128.0/1 172.18.12.193 UGSc utun3</pre>
**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.
<pre>
default fe80:af3c:f23e:8e26:20e1%en0 UGcg en0
default fe80::%utun0 UGcIg utun0
default fe80::%utun1 UGcIg utun1
default fe80::%utun2 UGcIg utun2
2000::/3 utun3 USc utun3</pre>
**Note:** We are not just looking for the default but also for any VPN that overrides the public v6 address space.
<br>
## Debugging DHCP for both IPv4 and IPv6
To get a look at the low level DHCP configuration (Mac/Linux):
```ipconfig getpacket en0```
<pre>
...
domain_name_server (ip_mult): {30.31.187.40, 189.74.19.55}
end (none):
...</pre>
So, in the above we are not getting IPv6 DNS servers from the DHCPv4 reply but...
```ipconfig getv6packet en0```
<pre>
DHCPv6 REPLY (7) Transaction ID 0x80940b Length 76
Options[4] = {
CLIENTID (1) Length 14: DUID LLT HW 1 Time 668691856 Addr 51:c9:3e:bd:f5:7c
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 3b:27:06:aa:62:f9
}</pre>
## Fixing Connectivity Issues with Wired and Wireless Networks
When it comes to transmitting data at the physical and data layer, you have the option to use either a wired or wireless (Wi-Fi) medium to send the data to your router.
### Troubleshooting Tips for Apple macOS / OSX
Regardless of whether you are using OSX/macOS versions like `10.11.7`, `11.5.8`, or `12.2.9`, 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 crucial, especially for teams that are fully embracing remote work and Work From Anywhere (WFA).
#### Using Built-in Scripts to Assist
One useful tool on OSX/macOS is `sudo wdutil info`, which provides a dump of current wireless related settings to the CLI and can also be configured to generate specific troubleshooting logs. Moreover, the `sysdiagnose` tool can be used to generate a wide range of logs, although most of these are related to wireless only, similar to wdutil.
Running `sudo nohup /usr/bin/sysdiagnose -u &` in the background will write logs to `/var/tmp/<blah>.tar.gz` for you. Alternatively, if you prefer to run it interactively, you can do so by running `sudo /usr/bin/sysdiagnose`, which will give 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 or use Cmd+Shift+G to point Finder to the path. Keep in mind that the file sizes are approximately 300MB.
## Possibly Helpful Videos
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|Video | Title | Channel |
| :---: | :---: | :---: |
|<a href="https://www.youtube.com/watch?v=s0FBo08Sw4A" data-lity><img src="https://i.ytimg.com/vi/s0FBo08Sw4A/default.jpg" class="img-fluid"></a>|<a href="https://www.youtube.com/watch?v=s0FBo08Sw4A" data-lity>Solving Wi-Fi problems in record time John Anderson WLPC US Phoenix 2017</a>|<a target="_blank" href="https://www.youtube.com/channel/UCIzBSS46vcqhwmBZ7ZpY-yg" >Wireless LAN Professionals</a>|
|<a href="https://www.youtube.com/watch?v=EWURmcra5_4" data-lity><img src="https://i.ytimg.com/vi/EWURmcra5_4/default.jpg" class="img-fluid"></a>|<a href="https://www.youtube.com/watch?v=EWURmcra5_4" data-lity>Wireless Association & Authentication Pass-Fail Brian Long WLPC US Phoenix 2017</a>|<a target="_blank" href="https://www.youtube.com/channel/UCIzBSS46vcqhwmBZ7ZpY-yg" >Wireless LAN Professionals</a>|
|<a href="https://www.youtube.com/watch?v=9RzmyNRK9e4" data-lity><img src="https://i.ytimg.com/vi/9RzmyNRK9e4/default.jpg" class="img-fluid"></a>|<a href="https://www.youtube.com/watch?v=9RzmyNRK9e4" data-lity>Wireless Packet Captures with Multiple Adapters Yer Yang WLPC Phoenix 2019</a>|<a target="_blank" href="https://www.youtube.com/channel/UCIzBSS46vcqhwmBZ7ZpY-yg" >Wireless LAN Professionals</a>|
|<a href="https://www.youtube.com/watch?v=p_K9xHxFM8Y" data-lity><img src="https://i.ytimg.com/vi/p_K9xHxFM8Y/default.jpg" class="img-fluid"></a>|<a href="https://www.youtube.com/watch?v=p_K9xHxFM8Y" data-lity>IEEE 802 11kvr Perry Correll WLPC Phoenix 2019</a>|<a target="_blank" href="https://www.youtube.com/channel/UCIzBSS46vcqhwmBZ7ZpY-yg" >Wireless LAN Professionals</a>|
|<a href="https://www.youtube.com/watch?v=r9oXNxgAKhM" data-lity><img src="https://i.ytimg.com/vi/r9oXNxgAKhM/default.jpg" class="img-fluid"></a>|<a href="https://www.youtube.com/watch?v=r9oXNxgAKhM" data-lity>Benefits of WPA3, Enhanced Open, and Easy Connect P. Ebbecke, P. Correll WLPC Prague 2018</a>|<a target="_blank" href="https://www.youtube.com/channel/UCIzBSS46vcqhwmBZ7ZpY-yg" >Wireless LAN Professionals</a>|
<center><small>Table 1.0 - Video Help</small></center>
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