How Can I Support Wifi Connectivity
Understanding IP Addressing
When using the Internet, you are assigned a unique Public IPv4 address, such as 176.206.197.168, or an IPv6 address, like 2000:f9a7:a284:39f7:cd69:5b18:3ade:137e. You can verify your IP address at https://test-ipv6.com/. However, explaining these addresses to non-technical individuals, and referencing MAC addresses like 62:49:4f:8c:24:96, can be complex and error-prone. Moreover, this information does not provide historical data, especially when dealing with past issues.
How Web Pages Are Accessed
When accessing a web page, such as https://mcglynn-fisher.info, you first query a DNS server to translate the host portion (mcglynn-fisher) and the Top Level Domain (info) of the URL to an IP address, for example, 84.70.170.42. In every web request, your computer and browser include the user-agent identifier, like
Mozilla/5.0 (compatible; MSIE 9.0; AOL 9.7; AOLBuild 4343.19; Windows NT 6.1; WOW64; Trident/5.0; FunWebProducts)
Understanding Default Gateways
Your default gateway is typically an automatically assigned address via DHCP, such as 10.166.175.119 (although they typically end in .1 or .254 based on the scope size). This is the designated destination where your computer sends all its traffic to be routed onwards. For IPv6, we offer an in-depth guide on how-to-fix-ipv6-connectivity/, and you can check this on Mac or Linux using:
Some command line code here
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 10.166.175.119 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:bd37:da8e:195a:ee13%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): {252.248.191.190, 23.220.10.133}
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 62:49:4f:8c:24:96
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 51:7c:5f:62:dd:5c
}
Resolving Issues with Wired and Wireless Connections
When it comes to transferring data to your router, you may encounter issues related to the physical and data layers, especially if you are using a wireless (Wi-Fi) or wired medium.
Troubleshooting Solutions for Apple macOS / OSX
Regardless of whether you are operating on OSX/macOS version 10.14.5, 11.3.7, or 12.2.7, there are various tools available for troubleshooting. However, these manual actions and scripts fail to provide a series of correlated values over time, making it challenging to identify the root cause of the problems. This is particularly problematic for remote teams and those engaged in Work From Anywhere (WFA).
Useful Built-in Scripts
An effective tool on OSX/macOS is the sudo wdutil info, which provides a detailed dump of current wireless settings through the CLI. It can also be configured to generate specific logs for troubleshooting purposes. Alternatively, the sysdiagnose tool offers a more comprehensive approach, generating a wide range of logs, although many relate to wireless connectivity only, similar to wdutil.
To run sudo nohup /usr/bin/sysdiagnose -u & in the background and generate logs in /var/tmp/<blah>.tar.gz, or for an interactive approach, you can execute sudo /usr/bin/sysdiagnose, taking note of the large file sizes, typically around 300MB.
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