How Do You Understand Apple Internet
Functionality of Internet Addressing
When using the Internet, individuals may be assigned a Public IPv4 address, such as 190.146.188.90, or an IPv6 address, such as 2000:3e69:f44a:2f7b:5880:c8c:d4fe:4bd. This information can be verified through https://test-ipv6.com/. However, for those who are not well-versed in technology, attempting to convey these complex addresses, or even referencing MAC addresses like 42:be:76:34:a1:33, can be prone to errors and quickly become complicated. Moreover, this method does not provide any historical data, particularly regarding previous issues.
Navigating the Internet
To access a website such as https://goodwin.name, the initial step is to contact a DNS server in order to convert the host portion (goodwin) combined with the Top Level Domain (name) of the URL into an IP address, such as 75.101.5.191. Whenever a web request is made, the computer and browser actually convey its type, for example: Opera/9.80 (X11; Linux i686; Ubuntu/14.10) Presto/2.12.388 Version/12.16
Significance of Default Gateways
Typically, the default gateway is an automatically configured address through DHCP. An example of a default gateway is 172.16.58.5 (commonly ending in .1 or .254, depending on the scope size), which is where the computer redirects all of its traffic for further routing. For an in-depth guide on how to address this for IPv6, visit how-to-fix-ipv6-connectivity/, or check on Mac or Linux 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 172.16.58.5 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:d008:3fa:7095:35c2%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): {85.126.11.158, 233.209.88.28}
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 42:be:76:34:a1:33
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 b6:07:5a:39:e9:7a
}
Solutions for Wired and Wireless Connection Issues
When it comes to sending data to your router, you may encounter problems with both wired and wireless (Wi-Fi) connections at the physical and data layers.
Troubleshooting Strategies for Apple macOS / OSX Users
Regardless of which version of OSX/macOS you are currently using - whether it’s 10.14.4, 11.2.1, or 12.0.5 - there are various methods and tools that can be utilized for troubleshooting. However, these manual approaches and scripts do not provide a series of interconnected values over a period of time. This is where automated remote troubleshooting becomes invaluable, especially for teams that have adopted a remote work and Work From Anywhere (WFA) approach.
Useful Built-in Scripts
One particularly useful tool for OSX/macOS is the sudo wdutil info command, which provides a dump of current wireless settings through the CLI and can also be configured to generate specific logs for troubleshooting purposes. Additionally, the sysdiagnose tool can be used to generate an extensive range of logs, although much of it pertains to wireless issues and is only relevant at a specific point in time, similar to wdutil.
Running sudo nohup /usr/bin/sysdiagnose -u & in the background will generate logs in /var/tmp/<blah>.tar.gz. If you prefer to run it interactively (although there isn’t much interaction involved), you can use the command sudo /usr/bin/sysdiagnose, which will prompt a privacy warning. When not run in the background, it should open Finder in the appropriate location, or you can navigate to /var/tmp directly, or use Finder with Cmd+Shift+G to navigate to the path. It’s important to be aware of the file sizes, which are approximately 300MB.
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