Fix Common Wifi Internet Issues
The Mechanism of Internet Addressing
When connecting to the Internet, you are assigned a Public IPv4 address, such as 246.73.129.31, or an IPv6 address like 2000:ee9a:a6f9:34e1:1994:857b:2147:e570. You can verify this information using https://test-ipv6.com/. However, for individuals who are not technologically inclined, conveying these addresses, or even reading out MAC addresses like 7d:b6:7f:cb:12:4e, can be prone to mistakes and can become cumbersome. Moreover, this method does not provide any historical data (especially relating to past issues).
Navigating the Internet
In order to access a website like https://yundt-feeney.info, you first connect to a DNS server to convert the host portion (yundt-feeney) in combination with the Top Level Domain (info) of the URL into an IP address, such as 75.17.118.43. Your computer and browser transmit their specifications with all web requests, for example: Opera/9.80 (X11; Linux i686; Ubuntu/14.10) Presto/2.12.388 Version/12.16
Understanding the Significance of Default Gateways
Your default gateway is typically an address that is automatically configured via DHCP. You receive a default gateway like 192.0.0.123 (although they generally end in .1 or .254 depending on the scope size), and this is where your computer sends all of its traffic to be routed onwards. For IPv6, we provide an in-depth discussion on how-to-fix-ipv6-connectivity/, but you can verify this 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 192.0.0.123 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:ee01:ec17:cfd7:2ceb%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): {103.7.90.85, 12.117.169.148}
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 7d:b6:7f:cb:12:4e
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 e1:4e:e6:88:90:75
}
Fixing Connectivity Issues in Wired or Wireless Networks
When it comes to sending data to your router, you may be utilizing either a wired or wireless (Wi-Fi) medium at the physical and data layer.
Resolving macOS / OSX Network Problems
Regardless of whether you are running OSX/macOS 10.11.1, 11.5.8, or 12.1.7, there are various troubleshooting tools available. However, these manual actions and scripts do not provide a set of correlated values over time. This is where automated remote troubleshooting becomes valuable, especially for teams that are adopting remote work and Work From Anywhere (WFA) practices.
Useful Built-in Utilities
A very useful 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. Additionally, the sysdiagnose tool can be used to generate a wide range of logs, although much of it is related to wireless and is point-in-time only, similar to wdutil.
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, use the command sudo /usr/bin/sysdiagnose and be aware of the large file sizes, around 300MB.
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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 🏠🏝🛰.
