How Do You Check Mac Internet
Understanding Internet Addressing
When connecting to the Internet, you are assigned a Public IPv4 address, such as 173.84.167.179, or an IPv6 address like 2000:d571:5073:9ce3:79e6:275:59b8:56b1. You can check your address using https://test-ipv6.com/. Communicating or referencing these addresses for non-technical individuals is prone to errors and becomes complex. Moreover, it lacks historical data, especially for past issues.
Navigating the World Wide Web
Accessing a website like https://hyatt-oreilly.io involves sending a request to a DNS server to translate the combination of the host (hyatt-oreilly) and the Top Level Domain (io) to an IP address such as 199.165.232.197. Your computer and browser provide information about themselves 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.
Significance of Default Gateways
The default gateway is typically automatically configured through DHCP and is usually an address like 192.168.75.104 (commonly ending in .1 or .254 depending on the scope size). This is the point where your computer directs all its traffic to be routed further. For IPv6, detailed instructions can be found in our blog how-to-fix-ipv6-connectivity/, and you can check on Mac or Linux using the following command:
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 192.168.75.104 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 fe80:3e7b:17e5:1d4c:facc%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): {144.48.61.104, 7.34.181.13}
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 43:13:89:2a:23:99
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 87:e4:da:55:7f:30
}
Fixing Issues with Wired or Wireless Networks
When it comes to sending data to your router, you may be utilizing a wired or wireless (Wi-Fi) medium at the physical and data layer.
Troubleshooting Tips for Apple macOS / OSX Users
Regardless of whether you are using OSX/macOS versions such as 10.14.1, 11.5.3, or 12.3.1, there are various tools available for troubleshooting. However, these manual actions and scripts do not provide a series of correlated values over time. This is where automated remote troubleshooting becomes invaluable, especially for teams that practice remote work and Work From Anywhere (WFA).
Utilizing Built-in Scripts to Aid in Troubleshooting
One incredibly useful tool for OSX/macOS is sudo wdutil info, which provides a dump to the CLI of current wireless related settings and can also be configured to generate specific logs for troubleshooting. Furthermore, the sysdiagnose tool can be used to generate a comprehensive range of logs, although much of it is only relevant at a specific point in time in relation to wireless, similar to wdutil.
To run the sysdiagnose tool in the background and write logs to /var/tmp/<blah>.tar.gz, you can use the command sudo nohup /usr/bin/sysdiagnose -u &. If you prefer to run it interactively, you can use sudo /usr/bin/sysdiagnose and it will 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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