How Do You Check OSX Internet
Understanding Internet Address Assignment
When using the Internet, your device may be assigned a public IPv4 address such as 183.72.98.156 or an IPv6 address like 2000:c127:5d75:99b5:256b:ec12:f99d:199. These addresses can be verified at https://test-ipv6.com/. However, for those who are not technologically inclined, transmitting and communicating these addresses, or even mentioning MAC addresses like f7:de:a8:01:73:b9, can be prone to errors and quickly become complex. Furthermore, this method does not provide any historical data, particularly from previous incidents.
Navigating the Internet
In order to access a website, such as https://braun.co, you first contact a DNS server to convert the host portion (braun) along with the Top Level Domain (co) of the URL into an IP address, such as 200.245.157.30. When making web requests, your computer and browser send their 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
By default, your gateway is usually an address assigned automatically through DHCP. Typically, the default gateway is something like 192.168.88.111 (although it generally ends in .1 or .254 based on the scope size), and it serves as the point where your computer forwards all its traffic to be routed onward. For IPv6, a detailed guide is available on how-to-fix-ipv6-connectivity/ and it can be verified 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 192.168.88.111 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 fe80:3759:3b3c:bc8b:1184%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): {198.242.43.28, 250.169.169.228}
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 f7:de:a8:01:73:b9
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 75:fb:89:9f:2a:8a
}
Resolving Issues with Wired and Wireless Connectivity
When transmitting data, whether through a physical connection or wirelessly via Wi-Fi, the medium used to send the data to your router can affect the troubleshooting process.
Tips for Addressing Problems on Apple macOS / OSX
Irrespective of the version of OSX/macOS you are using, whether it’s 10.12.7, 11.4.3, or 12.3.4, there are a variety of troubleshooting tools available. However, these manual actions and scripts do not provide a series of correlated values over time. This is where automated remote troubleshooting becomes particularly useful, especially for teams that have adopted remote work and the Work From Anywhere (WFA) approach.
Useful Built-in Scripts
One valuable tool on OSX/macOS is sudo wdutil info, which provides a dump of the current wireless settings to the CLI, and can also be configured to generate specific logs for troubleshooting purposes. Furthermore, the sysdiagnose tool can be used to produce a wide range of logs, although much of this information is only relevant at a specific point in time, similar to wdutil.
By running sudo nohup /usr/bin/sysdiagnose -u &, the tool will operate in the background and write logs to /var/tmp/<blah>.tar.gz. For interactive use, you can run sudo /usr/bin/sysdiagnose (although there is minimal interaction) and it will issue a privacy warning. When not run in the background, it should open Finder in the correct location, or you can navigate to /var/tmp or use Finder with Cmd+Shift+G to locate the path. However, be cautious of the large file sizes, which can be around 300MB or more.
Possibly Helpful Videos
P.S. Tips For Remote Network and Client Support
Digital work requires reliable connectivity. Whether for low latency or regular data streams, Wi-Fi, DNS, and network issues cause teams to lose time and productivity. Even worse is when support teams waste time trying to recreate and isolate issues! See how PanSift saves time, money, and frustration on all sides with instant remote troubleshooting 🏠🏝🛰.
