How Do You Support Wifi Router Issues
The Functioning of Internet Addressing
When using the Internet, individuals could be assigned a Public IPv4 address, such as 226.65.151.216, or an IPv6 address, such as 2000:451d:d09f:acae:2bfe:84f8:dc6a:ffe0. Verification of this can be done at https://test-ipv6.com/. However, relaying these addresses or MAC addresses, such as 8d:97:13:af:d1:3a, to those not familiar with technology can lead to errors and complications. Furthermore, there is a lack of historical data.
Navigating the Internet
When attempting to access a webpage, such as https://gibson-morar.net, one must initially contact a DNS server in order to convert the host portion (gibson-morar) along with the Top Level Domain (net) of the URL to an IP address, such as 160.172.255.140. Each web request from a computer and browser includes its 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
The default gateway is generally an address configured automatically through DHCP. An example being 172.17.183.225 (typically ending in .1 or .254 based on the scope size), this is where a computer sends all traffic to be routed onwards. For IPv6, more information can be found at how-to-fix-ipv6-connectivity/, but verification can be done 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 172.17.183.225 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 fe80:5f92:7035:a452:933d%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): {88.43.49.156, 166.168.58.10}
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 8d:97:13:af:d1:3a
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 19:57:ba:67:7b:92
}
Resolving Connectivity Issues for Wired and Wireless Networks
Whether you are utilizing a wired or wireless (Wi-Fi) medium to transmit data to your router, connectivity issues at the physical and data layer can be frustrating.
Troubleshooting Tips for Apple macOS / OSX
No matter which version of OSX/macOS you are operating on, be it 10.14.9, 11.2.5, or 12.1.5, there is a variety of tools available for troubleshooting. However, these manual actions and scripts do not provide a set of correlated values over time. This is where automated remote troubleshooting becomes invaluable, especially for teams that are engaged in remote work and Work From Anywhere (WFA) setups.
Useful Built-in Scripts
One of the most useful tools on OSX/macOS is the sudo wdutil info command, which provides a dump to the CLI of current wireless related settings and can also be configured to generate specific logs for troubleshooting. Additionally, the sysdiagnose tool can be used to generate a wide range of logs, although much of it is only related to wireless settings and is not time-based, similar to wdutil.
To run it in the background, use sudo nohup /usr/bin/sysdiagnose -u & and it will write logs to /var/tmp/<blah>.tar.gz. If you prefer to run it interactively (although there is minimal interaction), use sudo /usr/bin/sysdiagnose and it will trigger 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 file sizes, as they are typically around 300MB.
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