How Can I Check Apple No-access
Understanding Internet Addressing
When using the Internet, you are assigned a unique public IPv4 address like 56.156.117.217 or an IPv6 address like 2000:d8b9:9c05:469:18d:764f:1356:71ae. To check your address, you can visit https://test-ipv6.com/. However, trying to communicate these addresses or MAC addresses like 25:e5:76:66:23:31 can be prone to errors, especially for those without a technical background. Additionally, this method does not provide historical data, particularly for past issues.
Navigating the World Wide Web
When trying to access a website like https://wehner.biz, your computer first contacts a DNS server to translate the host name (wehner) combined with the Top Level Domain (biz) to an IP address like 246.129.33.55. Additionally, your web requests include information about your computer and browser type, for example: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2228.0 Safari/537.36
The Significance of Default Gateways
Your default gateway is typically assigned automatically through DHCP and often ends in .1 or .254, depending on the size of the network. This is where your computer routes all of its outgoing traffic. For troubleshooting IPv6 connectivity issues on Mac or Linux, more information can be found at how-to-fix-ipv6-connectivity/.
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 172.17.197.72 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 fe80:6942:7e00:7407:e818%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): {105.254.211.104, 205.173.50.45}
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 25:e5:76:66:23:31
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 ff:0b:5d:5b:71:d8
}
Resolving Connectivity Issues for Wired and Wireless Networks
When it comes to the physical and data layer, you may utilize either a wired or wireless (Wi-Fi) medium to transmit data to your router.
Strategies for Troubleshooting on Apple macOS / OSX Devices
Regardless of the version of OSX/macOS you’re using, whether it’s 10.13.5, 11.5.4, or 12.1.1, there are various tools available for troubleshooting. Unfortunately, manual actions and scripts do not provide a set of correlated values over time. This is where automated remote troubleshooting shines, especially for teams that embrace remote work and Work From Anywhere (WFA).
Utilize In-Built Scripts for Assistance
One extremely useful tool on OSX/macOS is sudo wdutil info, 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 can be used to generate a wide range of logs, although much of it is only related to wireless settings at a specific point in time, similar to the wdutil tool.
By running sudo nohup /usr/bin/sysdiagnose -u &, the tool will run in the background and write logs to /var/tmp/<blah>.tar.gz for you. If you prefer to run it interactively (although there is not much interaction), you can run
sudo /usr/bin/sysdiagnose and it will display 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. Keep in mind that the file sizes are approximately 300MB.
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