How Do You Fix Mac Issues
Demystifying Internet Addressing
When connecting to the Internet, you are assigned a Public IPv4 address, such as 123.162.88.51, or an IPv6 address, like 2000:77b8:576f:3eb6:a863:9d8f:4aa2:2aed. You can verify this by visiting https://test-ipv6.com/. However, conveying these addresses, or even mentioning MAC addresses, such as da:ef:b3:b2:92:c6, can be error-prone and complex for those not well-versed in technology. Furthermore, this does not provide any historical data, particularly from previous issues.
Navigating the World Wide Web
When accessing a web page, like https://goldner.info, you first contact a DNS server to convert the host portion (goldner) combined with the Top Level Domain (info) of the URL into an IP address, such as 79.146.138.241. Your computer and browser also include their type with all web requests. For example:
Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2228.0 Safari/537.36
Understanding the Significance of Default Gateways
Your default gateway is typically an automatically assigned address via DHCP, such as 172.23.183.182 (although they often end in .1 or .254 depending on the scope size). This is where your computer directs all its traffic to be routed onwards. For IPv6, a detailed guide on how to fix IPv6 connectivity is available, and you can check on Mac or Linux using:
```bash
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 172.23.183.182 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 fe80:9fcd:372:c222:f2f5%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): {8.177.194.124, 38.155.131.14}
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 da:ef:b3:b2:92:c6
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 44:73:a5:1a:bc:36
}
Fixing Wired and Wireless Connection Issues
When it comes to transmitting data to your router, you may be utilizing a wired or wireless (Wi-Fi) medium at the physical and data layer.
Troubleshooting Solutions for Apple macOS / OSX
Regardless of whether you are running OSX/macOS 10.15.4, 11.2.7, or 12.0.8, there are various troubleshooting tools available. However, these manual interventions and scripts do not provide a series of correlated values over time. This is where automated remote troubleshooting becomes essential, especially for teams that are embracing remote work and the Work From Anywhere (WFA) concept.
Utilizing Built-in Scripts for Assistance
One useful tool on OSX/macOS is the sudo wdutil info command, which provides a dump to the CLI of current wireless settings and can also be configured to generate specific logs for troubleshooting. Moreover, the sysdiagnose tool can be used to generate a wide range of logs, although many are only relevant at a specific point in time in relation to wireless, similar to the wdutil tool.
To run sysdiagnose in the background and write logs to /var/tmp/<blah>.tar.gz, use the command sudo nohup /usr/bin/sysdiagnose -u &. If you prefer to run it interactively, you can use the command sudo /usr/bin/sysdiagnose which will give 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. However, be cautious of the file sizes, which are typically around 300MB.
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