How Can I Support Common Wifi Connectivity
Explanation of Internet Addressing
When using the internet, one may have a Public IPv4 like 211.157.33.111 or an IPv6 similar to 2000:517b:a43d:60a1:5b96:fdb9:d5af:a99a. The platform https://test-ipv6.com/ can be utilized to verify this. However, for those who are not technologically inclined, relaying these addresses or even referring to MAC addresses such as 10:5c:87:46:a9:63 can be prone to mistakes and can become complicated rather quickly. Furthermore, this method does not provide historical data, particularly from past issues.
Navigating the World Wide Web
When attempting to access a web page like https://prosacco-spencer.info, the initial step is to connect with a DNS server to convert the host part (prosacco-spencer) along with the URL’s Top Level Domain (info) to an IP address, such as 187.7.249.232. With every web request, your computer and browser transmit its type, for instance:
Mozilla/5.0 (compatible; MSIE 9.0; AOL 9.7; AOLBuild 4343.19; Windows NT 6.1; WOW64; Trident/5.0; FunWebProducts)
Understanding the Significance of Default Gateways
By default, the gateway is usually configured automatically via DHCP. Typically, your computer receives a default gateway, like 192.168.255.146 (frequently ending in .1 or .254 based on the size of the scope). This is the destination where your computer forwards all of its traffic to be sent out. For IPv6, there is an extensive guide on how-to-fix-ipv6-connectivity/, and can be verified on Mac or Linux using the following command:
Command Line for Mac or Linux
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 192.168.255.146 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 fe80:4bb3:b1f1:74fd:5764%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): {121.84.252.36, 184.84.183.28}
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 10:5c:87:46:a9:63
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 6f:9f:50:e8:03:ab
}
Fixing Issues with Wired and Wireless Network Connections
When it comes to sending data to your router, you might be using a wired or wireless (Wi-Fi) medium at the physical and data layer.
Tips for Troubleshooting on Apple macOS / OSX
No matter which version of OSX/macOS you’re using - whether it’s 10.11.5, 11.5.7, or 12.2.2 - there are various tools available for troubleshooting. However, these manual actions and scripts lack the ability to provide a series of correlated values over time. This is where automated remote troubleshooting becomes essential, particularly for teams that operate remotely and embrace Work From Anywhere (WFA).
Using Built-in Scripts for Assistance
One useful tool on OSX/macOS is the sudo wdutil info command, which provides a dump of current wireless settings to the CLI and can also be configured to generate specific logs for troubleshooting. Additionally, the sysdiagnose tool offers a comprehensive range of logs, although much of it is limited to point-in-time information related to wireless, similar to wdutil.
To run sysdiagnose in the background and generate logs in /var/tmp/<blah>.tar.gz, you can use the 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 file sizes of around 300MB.
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