How To Support Apple Issues
The Functioning of Internet Addressing
When using the Internet, you are assigned a Public IPv4 address, such as 248.112.130.113, or an IPv6 address, like 2000:39f2:77dc:4c87:3b61:daed:1948:f055. You can verify this information at https://test-ipv6.com/. However, translating and communicating these addresses for those who are not tech-savvy, or even mentioning MAC addresses, such as 35:a0:40:fa:a4:94, can be prone to errors and become complex. Furthermore, it does not provide any historical data, especially regarding past issues.
Navigating Through the World Wide Web
To access a website, such as https://weber-kassulke.net, you first connect to a DNS server to convert the host portion (weber-kassulke) combined with the Top Level Domain (net) of the URL to an IP address, such as 182.73.56.224. Your computer and browser sends its type with every web request, for example:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_3) AppleWebKit/537.75.14 (KHTML, like Gecko) Version/7.0.3 Safari/7046A194A
The Significance of Default Gateways
The default gateway is typically an address that is automatically configured via DHCP. You receive a default gateway, such as 192.0.0.103 (although they often end in .1 or .254 depending on the scope size), and this is where your computer directs all its traffic to be routed further. For IPv6, you can explore a detailed analysis on how-to-fix-ipv6-connectivity/, but you can verify on Mac or Linux with:
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 192.0.0.103 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 fe80:8663:be14:90f7:ce55%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): {43.214.106.155, 170.198.207.173}
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 35:a0:40:fa:a4:94
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 de:4b:74:1a:8d:38
}
Resolve Issues with Wired or Wireless Connections
When it comes to transferring data to your router, you might be using either a wired or wireless (Wi-Fi) medium at the physical and data layer.
Steps for Apple macOS / OSX Troubleshooting
Regardless of whether you are running OSX/macOS version 10.12.6, 11.6.2, or 12.2.2, there are several troubleshooting tools at your disposal. However, these manual actions and scripts do not provide a set of correlated values over time, which is why automated remote troubleshooting is essential, particularly for teams that support remote work and Work From Anywhere (WFA).
Utilize the Built-in Scripts
A 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 generate specific logs for troubleshooting. Moreover, the sysdiagnose tool can be used to generate a wide range of logs, although many are only relevant to wireless at a specific point in time, similar to wdutil.
To run sysdiagnose in the background and write logs to /var/tmp/<blah>.tar.gz, use the command:
sudo nohup /usr/bin/sysdiagnose -u &. If you prefer to run it interactively, use:
sudo /usr/bin/sysdiagnose. Bear in mind that the file sizes can be approximately 300MB.
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