How Can I Fix OSX Issues
Explanation of Internet Addressing
When using the Internet, you are assigned a Public IPv4 address, such as 221.190.151.246, or an IPv6 address, like 2000:f389:e1d6:371a:d45a:817e:8fa:4165. You can verify this information by visiting https://test-ipv6.com/. However, conveying these addresses to individuals who are not technically savvy or even referring to MAC addresses, like 51:ae:54:50:1b:5e, can be prone to errors and can quickly become complicated. Also, there is a lack of historical data, particularly relating to previous issues.
Navigating the World Wide Web
When attempting to access a website, such as https://morar.co, you first connect to a DNS server in order to convert the host portion (morar) combined with the Top Level Domain (co) of the URL into an IP address, for example 194.199.161.32. Your computer and browser also include its type in all web requests, for instance:
Opera/9.80 (X11; Linux i686; Ubuntu/14.10) Presto/2.12.388 Version/12.16
The Significance of Default Gateways
Typically, your default gateway is an automatically configured address through DHCP, such as 192.168.251.129 (although they usually end in .1 or .254 depending on the scope size). This is where your computer directs all its traffic for further routing. For information on setting up IPv6, refer to our detailed guide on how-to-fix-ipv6-connectivity/, or alternatively, 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 192.168.251.129 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:e4a0:976c:e2ff:732e%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): {28.146.241.99, 214.56.231.215}
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 51:ae:54:50:1b:5e
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 27:0b:80:3d:02:97
}
Fixing Connectivity Issues for Wired and Wireless Networks
When transmitting data to your router, you might be using either a wired or wireless (Wi-Fi) network at the physical and data layer.
Troubleshooting Guidance for Apple macOS / OSX
Regardless of the version of OSX/macOS you are using, whether it’s 10.13.8, 11.5.2, or 12.3.7, there are various troubleshooting tools available. However, these manual interventions and scripts do not provide a holistic view of correlated values over time. This is where automated remote troubleshooting becomes essential, particularly for teams that are engaged in remote work and the Work From Anywhere (WFA) model.
Native Scripts for Assistance
One useful tool on OSX/macOS is sudo wdutil info, which provides a detailed dump of current wireless settings via the CLI and can also be configured to generate specific troubleshooting logs. Furthermore, the sysdiagnose tool can be used to generate a wide range of logs, although many are only relevant to wireless connectivity at a specific point in time, similar to wdutil.
To run it in the background and save logs to /var/tmp/<blah>.tar.gz, use the command sudo nohup /usr/bin/sysdiagnose -u &. If you prefer to run it interactively (although there isn’t much interaction), use the command sudo /usr/bin/sysdiagnose, which 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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