How Can I DiagnOSe Apple Issues
Introduction to Internet Addressing
When using the Internet, individuals are assigned a Public IPv4 address or an IPv6 address, both of which can be checked using the website https://test-ipv6.com/. However, conveying or referencing these addresses, as well as MAC addresses, can be error-prone and complex, especially for those who are not technologically inclined. Moreover, this method does not provide any historical data, particularly related to past issues.
Navigating the World Wide Web
In order to access a website such as https://marquardt-gibson.biz, users initially connect to a DNS server to convert the host portion (marquardt-gibson) along with the Top Level Domain (biz) of the URL into an IP address. When making web requests, the computer and browser also transmit their type, 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
Understanding the Significance of Default Gateways
By default, a gateway is automatically assigned via DHCP, typically ending in .1 or .254 depending on the size of the scope. This designated gateway is where all traffic from the computer is routed. For IPv6 settings, a detailed explanation is available at how-to-fix-ipv6-connectivity/, and on Mac or Linux systems it can be checked 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 172.16.50.212 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:eca4:2fdb:fee4:b0ee%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): {78.11.252.131, 17.86.207.199}
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 31:4b:6b:3c:bf:4c
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 c6:6a:3b:f3:75:9d
}
Fixing Connectivity Issues for Wired and Wireless Networks
Whether you’re using a wired or wireless (Wi-Fi) connection at the physical and data layer, it’s important to ensure the smooth transmission of data to your router.
Troubleshooting Tips for Apple macOS / OSX Users
Regardless of your OSX or macOS version—be it 10.14.3, 11.6.9, or 12.1.3—there is a variety of troubleshooting tools available. However, these manual actions and scripts may not provide a consistent set of correlated values over time. This is where automated remote troubleshooting becomes invaluable, especially for teams engaged in remote work and Work From Anywhere (WFA) scenarios.
Using Built-in Scripts to Diagnose Issues
One valuable tool on OSX/macOS is the sudo wdutil info command, which provides a detailed dump of current wireless settings and can also generate specific logs for troubleshooting purposes. For a more comprehensive approach, the sysdiagnose tool can be employed to generate a wide range of logs, although many are only relevant to a specific moment in time, similar to wdutil.
To run sudo nohup /usr/bin/sysdiagnose -u & in the background and save the logs to /var/tmp/<blah>.tar.gz, or to run it interactively, simply execute sudo /usr/bin/sysdiagnose. However, keep in mind that the file sizes can be quite large, averaging around 300MB.
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 🏠🏝🛰.
