How Can I Support Common Wifi Internet Issues

Demystifying Internet Addressing

When using the Internet, you are assigned a Public IPv4 address such as 189.193.192.35 or an IPv6 address like 2000:10b6:2de5:d9:5560:695f:dcee:a85e. You can verify this information at https://test-ipv6.com/. However, communicating and managing these addresses, as well as MAC addresses like f0:60:aa:bd:6c:7b, can be error-prone for non-technical individuals. Furthermore, historical data regarding past issues isn’t readily available.

Unraveling Web Access

Accessing a website like https://veum-rowe.info involves initially reaching out to a DNS server to convert the host portion (veum-rowe) along with the Top Level Domain (info) of the URL into an IP address like 80.37.91.190. Notably, your computer and browser transmit their type with all web requests, for example:
Mozilla/5.0 (compatible; MSIE 9.0; AOL 9.7; AOLBuild 4343.19; Windows NT 6.1; WOW64; Trident/5.0; FunWebProducts)

Understanding the Significance of Default Gateways

The default gateway is typically an automatically configured address through DHCP. It’s usually in the form of 192.0.0.205 (although it often ends in .1 or .254 based on the scope size), and functions as the point where your computer directs all its traffic to be forwarded. Although we delve deeper into IPv6 in how-to-fix-ipv6-connectivity/, you can verify it 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  192.0.0.205    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:cfee:46f5:dfaa:963d%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): {233.128.127.67, 246.82.153.196}
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 f0:60:aa:bd:6c:7b
  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 38:59:fe:0e:36:38
}

Fixing Issues with Wired and Wireless Networks

When it comes to transmitting data to your router, you might be using a wired or wireless (Wi-Fi) medium at the physical and data layer.

Troubleshooting Tips for Apple macOS / OSX Users

Regardless of whether you are using OSX/macOS version 10.12.6, 11.1.1, or 12.0.3, there are various troubleshooting tools available. However, these manual actions and scripts do not provide a series of correlated values over time. This is where automated remote troubleshooting becomes valuable, especially for teams that work remotely or Work From Anywhere (WFA).

Helpful Built-in Scripts for Troubleshooting

One of the useful tools on OSX/macOS is the sudo wdutil info command, which provides a dump of current wireless settings to the CLI and can be configured to generate specific logs for troubleshooting. Additionally, the more comprehensive sysdiagnose tool can generate a wide range of logs, although many are only point-in-time observations related to wireless, similar to wdutil.

To run sysdiagnose in the background, use the command sudo nohup /usr/bin/sysdiagnose -u &, and it will write logs to /var/tmp/<blah>.tar.gz. Alternatively, you can run it interactively with the command sudo /usr/bin/sysdiagnose, but be mindful of the large file sizes, approximately 300MB or more.

Possibly Helpful Videos

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Table 1.0 - Video Help