Ok, in our next segment, we will discuss common problems
such as incorrectly configured SSID,
and look at some other tools that you can use within Wireshark
to help troubleshoot wireless related issues.
So as we discusse earlier, an SSID or service set identifier or identification
is used to associate you to a particular wireless network.
It is generally broadcasted in a certain area
so that you can see it and join. Again, sometimes it's hidden from you,
in cases where people want to keep it private.
But you can then connect to it and it'll allow you to join an AP or an access point
which constitutes a basic service set or BSS.
Once you're associated, you can then authenticate, join the network and participate.
All that comes from the SSID.
So there are time where you will try to connect to the network,
and you will not be able to do so and there are quite a few reasons for that.
Essentially, if you don't know the SSID and it's hidden from you
then you're going to have to find a way to find it.
Otherwise, if you do see it, you cannot join.
You're going to have other issues that may be associated to it,
such as if you associate but cannot authenticate or
other reasons, authentication reasons may be that you're using TACAC's or RADIUS
and your credentials are incorrect or it's not allowing you to join.
But as you can see, there's quite a few reasons why you would not be able to join
and Wireshark will in fact give you the answers to what's going on.
So, one of the tools that I want to use when digging into the capture,
specifically is, we showed the I/O graph in a separate module but
particularly, you can use and build an I/O graph
to further dig into what's going on in your network by writing filters.
So for example, here I wanted to see every 10 seconds
what was going on based on the channel that I had selected
and what wireless networks are out there.
So as you could see, specifically I was able to
plot or map on the x and y axes, some specific information based on
what I was seeing as per the 2 gigahertz range.
So there are some examples of tools that can be further customized
based on the technology in which you want to dig into
to find some data that will give you a clue into, for example,
a radio transmission may have an issue and you may be able to find that with these tools
based on the correct filters that you write.
So, just a reminder, you have to turn this off and on, so if you want to
view certain things, you have to enable them.
Within the I/O graph, similarly what I just showed you in the live demonstration,
you can write specific filters in and you can look at some,
some detailed information in the I/O graph.
So as you dig deeper into the capture, you can review the packets.
You can look deeper into the frames.
You can find some frame check sequence issues, channeling,
general association issues.
And again, if you have incorrect information or improper configurations on your wireless client,
it's likely that you're not going to be able to join
and within the capture, you're going to get your clues as to what that could be.
And the tools that you could use is the wireless LAN or
WLAN traffic tool, the I/O graph and you can drill into the capture window,
capture window and apply filters to further find issues with excessive beaconing or
incorrect channels and so on.
And as we showed earlier, there's also the other tool
where you can go in and basically filter on
any SSID that you see and further drill down into it.
Or you can select it and you can look for other issues related to it.
However, just remember that this tool will only be available if you have captured wireless traffic.
Otherwise, it will be grade out. Otherwise, and you will not be able to use it.
So just remember that when you're looking for problems in your wireless LAN network.
You obviously have to be capturing some wireless traffic to be able to
invoke the tools to be able to troubleshoot it.