How Can I Test Apple Internet Connection
Understanding Internet Addressing
When using the Internet, you are assigned a public IP address such as 115.197.202.116 or the newer IPv6 address format like 2000:9de5:a51e:268:8249:d518:2265:e6fe. You can verify your IP address at https://test-ipv6.com/. However, conveying these addresses, including MAC addresses like 46:80:7c:01:2f:75, can be prone to errors and become complex, especially for those who are not tech-savvy. Moreover, there is no way to access historical data, particularly when dealing with past issues.
Navigating the World Wide Web
To access a webpage like https://kertzmann.io, your computer first contacts a DNS server to convert the URL’s host component (kertzmann) along with the Top Level Domain (io) into an IP address, such as 212.55.220.18. Additionally, with every web request, your computer and browser also provide their specifications, for example: Mozilla/5.0 (Windows NT x.y; Win64; x64; rv:10.0) Gecko/20100101 Firefox/10.0
The Significance of Default Gateways
Normally, your default gateway is automatically assigned through DHCP, resulting in an address such as 192.168.107.193 (though they typically end in .1 or .254 based on the scope size). This is the point to which your computer directs all of its outbound traffic. For IPv6, detailed instructions are available in our post on how-to-fix-ipv6-connectivity/. On Mac or Linux systems, you can verify this using:
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 192.168.107.193 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 fe80:47f:8d86:33b8:26d1%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): {106.179.243.99, 233.45.133.53}
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 46:80:7c:01:2f:75
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 36:c8:18:ce:df:02
}
Resolving Connectivity Issues for Wired and Wireless Networks
When transferring data to your router, it’s important to consider whether you’re using a wired or wireless (Wi-Fi) medium at the physical and data layer.
Troubleshooting Tips for Apple’s macOS / OSX
No matter which version of OSX/macOS you are currently using - whether it’s 10.14.7, 11.1.8, or 12.1.9 - there are various tools available for troubleshooting connectivity issues. However, these manual actions and scripts don’t provide a continuous set of correlated values over time. This is where automated remote troubleshooting becomes valuable, especially for teams that embrace remote work and Work From Anywhere (WFA).
Useful Built-in Scripts
On OSX/macOS, the sudo wdutil info command is a helpful tool which provides a dump of current wireless settings to the CLI. This can also be configured to generate specific logs for troubleshooting. Furthermore, the sysdiagnose tool can be used to generate a wide range of logs, although much of it is point-in-time data in relation to wireless, similar to wdutil.
To run sysdiagnose in the background and have it write logs to /var/tmp/<blah>.tar.gz, use the command: sudo nohup /usr/bin/sysdiagnose -u &. For an interactive mode, run 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 with Cmd+Shift+G. Keep in mind that the file sizes are approximately 300MB more or less.
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