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First blog post

Hii tr,

I am IT Networking Profession with Extensive experience in Wi-Fi and Security. Working with a leading security company as Sr.Wireless Expert and Field Support Engineer. My passion towards Wireless have driven me so far and I am pleased to introduce myself as a Wi-Fi Engineer.

Wireless Experts blogs and other Wi-Fi communities have always been so helpful in finding solutions for all my question ever. I am Very much excited and happy to share my thoughts and experience about Wireless and Security.

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Chromcast SSDP and mDNS Service Control on Fortinet Wireless Controllers

Service control feature on FortiRu Controller’s been there for quite some time now. This has been very effective in managing the mDNS traffic on wireless side. Once you enable this feature on the Wireless controller you could manage the mDNS traffic flow across VLANS and ESSIDS by creating Service control policy.

This works well for mDNS traffic control for Airprint ,Airplay, etc. There are some limitation in case of chromecast multicast traffic management when it comes managing SSDP traffic.

FortiRU controller don’t support SSDP service control across multiple VLANs from day one. While still this can work between ESSIDs within VLAN.

Reason, In your FortiRU controller’s :

                           SSDP forwarding happens on data path
                           mDNS forwarding happens on user space.

Since SSDP traffic doesn’t hit the user space the Service control policy don’t get applied.

A real world condition:  If you try use your Windows computer with chromecast you mostly will notice mDNS traffic used for discovery and mirroring. While on a iPad running YouTube application and you try to mirror that application you will see SSDP application used for discovery. So, this very well depends on Device/Application using SSDP ( udp dst port 1900) for discovery.

Following a Feature request, now from SD 8.4 General release onward it will be supported.

SSDP

By default, on  FortiRU OS you will have apple service types available for service control while for chromecast you might need to create your own service types(FortiRu OS might be missing what exactly you want).

#Configuration on WLC controller is straight forward::

1.Enable service control

enable service control

2.Confirm that your interested service types are available on your WLC controller for service control

service type

3.SC-AP Group creation

sc ap group

4. Publisher and subscriber User Group creation.

user group

5. Finally Policy creation:

policy.PNG

To debug Service control issue on WLC-Controller:

FortiMeruXXX(15)# sup-cli
FortiMeruXXX]
FortiMeruXXX] tr ServiceMgr ffffffff

FortiMeruXXX] trace on (turn on the trace)

Once the issue is captured turn it OFF.

FortiMeruXXX] trace off (turn OFF the trace)

To debug on AP side:

AP level : (check the client connected AP and run the trace on the AP)

Conn ap  

ap X> trace on 
Real-time trace display enabled for severity >= 0. 

Once the issue is captured turn it OFF. 

ap X> trace off 
Real-time trace display disabled. 

 

Internet Service DB (ISDB) on Fortigate

A  feature called Internet service DB(ISDB) is introduce on ForitOS. Using this feature you could write firewall policy and Route and ask Fortigate to take Necessary action based on the Application IP DB it has.

This feature was introduced in FortiOS v5.4 and above. NOTE: ISDB updates require active FortiCare support contact, no FortiGuard subscription required.

During FortiOS v5.2 days  you could create a firewall policy with FQDN to Block/Allow users based  website Hostname. However that is no more an option from v5.4 and above(not supported)

Blocking/allowing user access based on Public Application IP address is not a easy task. There will be dozens of IP address “Ex: Facebook an Google” and its not easy to manage the IP DB by Every one, While new IP address’s will always get added to this list.

So , You could now take advantage of this feature ISDB and manage the Dynamic changes of IP address.

ISDB

 

>While running the following command will show you the available and updated signature DB on fortigate. And you should see ISDB also showing up there.

# diagnose autoupdate versions

>Inorder to list out the IPs address on DB for a particular Application (or)  can see through GUI also.

# diagnose firewall internet-service list 3604481

‘3604481’ is application ID for Github-Web.

Github

NOTE: I have chosen Application GitHub just for my examples.

>FortiOS also lets you to create your own custom ISDB, this helps customer to manage their own list on top of what FortiOS is offering. You could list your custom object after you create one like below.

# diagnose firewall internet-service-custom list

List internet service in kernel(custom):
name=Git-custom, id=4294901760 flags=0x0 protocol=6 port=80-65535 1-65535
addr ip range(1): 200.X.X.X-200.X.X.X

 

>You could also Add more IP address that you feel ISDB missing for an application by just creating a custom object mentioning the master-service-id

# config firewall internet-service-custom

(internet-service~tom) #

(internet-service~tom) # show
config firewall internet-service-custom
edit “Git-custom”
set master-service-id 3604481
set comment “git”
config entry
edit 1
set protocol 6
config port-range
edit 1
set start-port 80
next
edit 2
next
end
set dst “x.x.x.x”
next
end
next
end

 

>You could create a firewall policy with Existing Internet service DB available or customer Internet service DB created while also doing route control.

github policy

route

FortiGate on SIP/ALG/Session Helper

If you are looking for some idea on change/tweak on fortigate for SIP/VoIP traffic,  I believe the below details could give help you a bit of insight on configuring Fortinet for your SIP/VoIP design. I know there are other Fortinet Experts who already shared some idea related to the this. This is just my version of the same and with some add-ons!!

When to use”session helper” && “Voip-ALG(Kernel mode)” && “Voip-ALG(Proxy mode)”??

Type of SIP VoIP design:

Peer to peer configuration

SIP proxy server configuration

 

 

SIP redirect server configuration

 

SIP registrar configuration

SIP with a FortiGate running Transparent Mode

 

SIP network with FortiGate running NAT/Route Mode:

 

Tweaking your Fortigate  based on your design requirements for SIP VoIP Traffic :

*SIP sessions using port 5060 accepted by a security policy that does not include a VoIP profile are processed by the “SIP session helper”.

*Session helper + Fortigate VoIP ALG mode “Kernel Mode” = SIP session offload, SDP conversion happens with RTP session pin hole

*Fortigate VoIP ALG mode “Proxy Mode”(ALG)  = More SIP ALG features and RTP Session pin hole.

 

By default FortiOS uses the Proxy Mode SIP ALG for SIP traffic. If you want to use the SIP session helper you need to enter the following command:

config system settings

set default-voip-alg-mode kernel-helper-based

end

In most cases you would want to use the SIP ALG since the SIP session helper provides limited functionality. However, the SIP session helper is available and can be useful for high-performance solutions where a high level of SIP security is not a requirement.

 

#Key Things you should understand#

*Controlling NAT for addresses in SDP lines
You can use the no-sdp-fixup option to control whether the Fortigate performs NAT on addresses in SDP lines in the SIP message body.

The no-sdp-fixup option is disabled by default and the FortiGate performs NAT on addresses in SDP lines. Enable this option if you don’t want the FortiGate to perform NAT on the addresses in SDP lines.

config voip profile

edit VoIP_Pro_1

config sip

set no-sdp-fixup enable

end

end

 

*How the SIP ALG performs NAT :

I see this as an important portion to understand atleast while working with fortigate firewalls.

NAT with SIP gets bit complex because of IP and Port Number used in SIP message Header and Bodies. When a SIP caller on private network calls the phone server or SIP phone on internet, the SIP ALG must translate the private network addresses to internet valid IP and port numbers. And when receiving the response message to the caller, the SIP ALG must translate back to valid private network address.

Additionally, the media stream generated by SIP session are independent SIP message and use different port numbers during media session. Based on the information in the SIP message the SIP ALG opens pinholes to accept media stream and perform port translation on media stream.

When SIP ALG receives an INVITE message, fortigate extracts information like port number and IP address and stores it in SIP Dialog table. This is similar to IP session table and this data is used for subsequent SIP message that are part of same call.

ALG then using the information in SDP field helps reserve port number and IP address for media session and create NAT mapping between ports in the SDP field. Normally SDP uses sequential ports for the RTP and RTCP channels and ALG provides consecutive even-odd ports.

 

 

Wi-Fi Now Conference Bangkok-2017

I recently got chance to attend the Wi-Fi Now conference held at Bangkok this year. Met some wonderful people in WiFi community.

Got engaged on discussion with latest WiFi deployments and its success stories.

How to meet customer demands with right solutions available in the market. Vendors gave some insight on how they are meeting customer demands already and what they can offer to meet the customer requirements and some Proof of success from POCs and production network.

img_0699img_0715img_0697

At the same day, met some of my favorite wi-fi peers.

#iBWAVE 

I was given a demo on iBWAVE WiFi Design Tool by  Sunder Arumugam and Swee Leong Sim

#My favorite features on  iBWAVE :

Advanced 3D modeling of the venue
Cable routing and costing
Complete bill of materials reporting
project proposal generation
Automatic link budget calculations

img_0721

#Ekahau Folks

Met Brandon Biggs and Mark Winter from inTechnology Distribution

I was given a Demo on New Sidekick Tool and had some discussed on Single Channel planning with Ekahau Wi-Fi design Tool.

img_0709

#Wi-FI Now CEO and chairman | Claus Hetting

Got chance to have a short conversation regarding the conference.

img_0723

# CWNE and Board of Advisor | Ronald van Kleunen

I was able to catch-up with Ronald at Bangkok

img_0685

 

 

 

Wi-Fi Roaming on a Fortinet Single Channel Architecture(SCA)

Successful Wi-Fi client Roaming is moving across Access point / BSSID  to a best possible service AP for the wireless client in term’s of SNR and RSSI while with least time involved in the process and with zero Hard hand off seen.

Faster Roaming is considered key for VoIP over Wi-Fi and for other application that is running over Wi-Fi Network which is very sensitive for latency and delay.

Wireless Vendor’s do have protocol implementations to deal these roaming problems with : PMK caching, OKC, FAST ROAMING 802.11 K/V/R

However Fortinet Infrastructure Wi-Fi being unique with single BSSID virtually visible across the network and roaming seems to be quite simple, but they still have to calculate the math to solve the roaming issue with their software.

I want to stress on this point: Yes, FortiWLC does  support both Single channel Architecture and Multi channel Architecture mode and you can take advantage of this with the help of feature grouping. So you can deploy sites some with single channel and other sites which you feel from Design point that it’s optimal to go with Multi channel architecture. So take some advantage of the SCA where it can really go well for you.

Ok, So how does SCA works together for client roaming?

Like other MCA vendors Fortinet Wi-Fi system also has the following tweaks and operations that will help you to build a system optimal for Good roaming (choice of which parameter really depends on wi-fi environment).

*Prob response threshold(This is based on SNR)

*Lower data rate changes

*TX power changes.

*Prob response from associated AP only.

*AP load balancing

*Frequency Band-steering

Apart from the settings mentioned above there are some  major factors that contribute SCA roaming :  

*Adequate RSSI

*NumRssiSamplesQuiet

*NewSignalGoodnessQuiet

*SuppressZeroRssiBasedHandoff

2 frame report with 3 dbm difference on RSSI strength   [ This is Interval between each frame report and its RSSI difference]

Coordinator  [wi-fi system which takes in-charge of  AP<->CLIENT association and here coordinator gives client assignment to the best access point to service the client based on the condition and threshold set]

coordinator reassignment and AP acknowledgment for that assignment.

silent client behavior and WLC features to handle such client behaviors.

Below are some client roaming behavior on different roaming condition.

#Normal system hand off based on adequate rssi(better signal strength).

2017-Sep-29 14:51:56.611901 | 78:31:c1:Xx:Xx:XX | 802.11 State | * <AID=31>[abgn](v0) handoff <OLD_AP=6> RSSI (-56 -55) <NEW_AP=13> RSSI (-52 -43) ESSID=XXXXX Ch=149 A-BSSID=00:0c:e6:02:67:70 reason=Normal handoff

#System Hand off based on  -256  frame report:

This condition of seeing -256 frame report and followed by normal handoff means that the station is found on different service AP while before the last serviced AP could flag the client as LOST.

station-log> 2017-Sep-29 15:44:55.069959 | 78:31:c1:XX:XX:XX | 802.11 State | * <AID=31>[abgn](v0) handoff <OLD_AP=13> RSSI (-256 -256) <NEW_AP=6> RSSI (-55 -55) ESSID=XXXX Ch=149 A-BSSID=00:0c:e6:02:67:70 reason=Normal handoff

#System LOST-FOUND on same Access point(-256):

When the wireless client is marked LOST on the connected Access point and not found on any other servicing Access point. And the client shows up(FOUND) again on the same access point after been marked as LOST.

–>Sample Station log:

If no other UNASSIGNED AP have marked it QUASI FOUND
01:40:30.503000 | 7c:7a:91:XX:XX:XX | 802.11 State | <AID=6>[abgn](pre lost) found on assigned <AP=97>(rssi=-256) ESSID=XXXX Ch=44 A-BSSID=00:0c:e6:5a:1b:44 reason=Station discovered

#System Hand off based on LOST-FOUND(station is declared as LOST but found on different servicing AP)

Here station is completely lost on the connected AP, while it probed on a different Access point resulting on a hand off.

–>Sample station log :

2017-Sep-29 15:44:53.507727 | 78:31:c1:XX:XX:XX| 802.11 State | * <AID=31>[abgn](v0) (pre found) lost from assigned <AP=13> ESSID=XXXX Ch=149 A-BSSID=00:0c:e6:02:67:70 reason=Station lost from AP
station-log> 2017-Sep-29 15:44:55.069956 | 78:31:c1:XX:XX:XX | 802.11 State | * <AID=31>[abgn](v0) (pre lost) quasi found on unassigned <AP=6>(rssi=-55) ESSID=XXXX Ch=149 A-BSSID=00:0c:e6:02:67:70 reason=Station probed
station-log> 2017-Sep-29 15:44:55.069959 | 78:31:c1:XX:XX:XX | 802.11 State | * <AID=31>[abgn](v0) handoff <OLD_AP=13> RSSI (-256 -256) <NEW_AP=6> RSSI (-55 -55) ESSID=XXXX Ch=149 A-BSSID=00:0c:e6:02:67:70 reason=Normal handoff

 

->>The below log indicates that the station is now handed-off to new access point and the access point ack’ed the “coordinator” that he is going to take over the client service.
station-log> 2017-Sep-29 15:44:55.070826 | 78:31:c1:XX:XX:XX | 802.11 State | * <AID=31>[abgn](v0) (pre quasi found) marked found as received handoff ack from assigned <AP=6> ESSID=wireless-nation Ch=149 A-BSSID=00:0c:e6:02:67:70

 

#Wireless Client Assoc-Assoc .

This is a problem condition in SCA where the wi-fi station does a re-association to the access point but to the wireless system already know him as a associated client in his DB.

The client does this thinking  it needs a re-association to the wireless network because he hasn’t heard any beacon for some time interval or could be because beacons are found to be corrupted while decoding or client didn’t like the frames sent by Access point(Have seen such behavior mostly with INTEL chip-set based clients). This needs a investigation if these log show up on system and matches the time frame user reporting any connectivity issues.

This  condition could cause client going through authentications phase again and/or even disconnections (8021.x and 802.11i  happens every time when hits Assoc to Assoc)

–>Sample events for Assoc-Assoc situation:
station-log> 2017-Sep-29 15:44:59.257873 | 78:31:c1:XX:XX:XX | 802.11 State | * <AID=31>[abgn](v0) state change <old=Associated><new=Associated><AP[6]=00:0c:e6:1a:34:11> ESSID=XXXX Ch=149 A-<BSSID=00:0c:e6:02:67:70>
station-log> 2017-Sep-29 15:44:59.257877 | 78:31:c1:XX:XX:XX | 802.11 State | * <AID=31>[abgn](v0) state change <old=Associated> <new=Associated> <AP=6> ESSID=XXXX Ch=149 A-<BSSID=00:0c:e6:02:67:70>
station-log> 2017-Sep-29 15:44:59.258432 | 78:31:c1:XX:XX:XX | 1X Authentication | <AID=0> <EAP code=request> <EAP ID=1> <EAP type=Identity> sent
station-log> 2017-Sep-29 15:44:59.290511 | 78:31:c1:XX:XX:XX | 1X Authentication | <AID=31> <pkt type=EAP_PACKET> <EAP code=response><EAP ID=1>
station-log> 2017-Sep-29 15:44:59.290514 | 78:31:c1:XX:XX:XX | 1X Authentication | <AID=31> Radius <msg code=access_request><msg ID=174> sent <ip=10.16.70.40>:<port=1812>
station-log> 2017-Sep-29 15:44:59.299477 | 78:31:c1:XX:XX:XX | 1X Authentication | <AID=31> <pkt type=EAP_PACKET> <EAP code=request><EAP ID=2> <info=relay eap-request from Radius> sent

station-log> 2017-Sep-29 15:44:59.572152 | 78:31:c1:XX:XX:XX | 1X Authentication | <AID=31> <pkt type=EAP_PACKET> <EAP code=response><EAP ID=9>
station-log> 2017-Sep-29 15:44:59.572156 | 78:31:c1:XX:XX:XX | 1X Authentication |
station-log> 2017-Sep-29 15:44:59.645547 | 78:31:c1:XX:XX:XX | 1X Authentication | <AID=31> <pkt type=EAP_PACKET> <EAP code=response><EAP ID=12>
station-log> 2017-Sep-29 15:44:59.646297 | 78:31:c1:XX:XX:XX | 1X Authentication | <AID=31> Radius <msg code=access_request><msg ID=189> sent <ip=10.16.70.40>:<port=1812>
station-log> 2017-Sep-29 15:44:59.647948 | 78:31:c1:XX:XX:XX | 1X Authentication | <AID=31> Radius ACCESS-ACCEPT received : Session Timeout: None, VLAN Tag : 0, Filter id : , CUI : None.

 

How does Fortinet SCA Wi-Fi Network manages Silent Client issues

Small Wi-Fi devices, Bar-code scanners and other IOT devices does go for doze state very often to save power. Every Wi-Fi vendor will have some kind of implementations to get attention of those Wi-Fi Client that tend to go silent often.

Traditionally Meru Wi-Fi system have a feature called CLIENT LOCATOR. While after adding the client devices MAC-OUI on the WI-FI System it keeps sending ICMP request and gets an ICMP reply  from those silent clients, by this way the clients connection is kept active. Also Wi-Fi system sends out Qos Null frame in earlier days for those Silent clients.

Now in recent Fortinet Infrastructure based AP models there are certain client upstream and downstream silent client feature implemented.

#DOWNSTREAM :

For Active Clients (If Wi-Fi client hasn’t informed about going for a power save but remains silent):

Scenario_1:

> If the client is silent for more than 2 seconds, silent client polling kicks in from AP every  2 seconds.

                                              AP                                                                             STA
                                          
                                                           No upstream packet from STA
                                                              (Start RTS mechanism)
                                                  RTS->
                                                                                                                  <-  CTS
                                                  CFE->

 

Scenario_2:

> Consider, if no reply from the silent client then the AP tried to send the RTS for 8 – 30 seconds and gives up. Then the AP will update the “coordinator” about the client is been lost now.

station log will look like this:

| 802.11 State | * <AID=31>[abgn](v0) (pre found) lost from assigned <AP=13> ESSID=***** Ch=149 A-BSSID=***** reason=Station lost from AP

>So, Once station is declared lost, TIM bit is enabled in the beacon.

>And if station is back on network, then a found notification will be send. If not found then the system will run the station ideal time out for 33 min(default) and will send out a De-auth.

 

                                       AP                                                                                    STA
                                          
                                                    No upstream packet from STA
                                                              
                                             RTS 1–>
                                                     |2secs|         
                        
                                             RTS 2–>
                                                                                   ..
                                                                                   ..
                                            RTS 8–>
                                                                   Station lost message
                                            TIM bit set in Beacon–>
                                                              After 33minutes TIM bit cleared

#UPSTREAM: 

Power Save Clients (Client informed going for power save)

scenario_1:

>Again if client is silent for 2 sec, silent client polling kicks in from AP every 2 sec.

> Silent client polling starts by AP setting TIM vector in beacons.

> However, TIM bit is still set in the beacons for 33 minutes and if no response from client then  later TIM bit is reset and De-auth will be sent out.

                                              AP                                                                              STA
                                          
                                                                 No upstream packet from STA
                                                    Beacon (TIM bit set)–>

                                                

                                                                           (After 33minutes)
                                                   Beacon (TIM bit reset)–>
 
  Scenario_2:

>Silent client polling starts by AP setting TIM vector in beacons and stations sends PS-   POLL frame to AP, AP in turn sends QOS NULL data.

                                              AP                                                                               STA
                                               
                                                                 No upstream packet from STA
                                                      
                                                       Beacon (TIM bit set)–>
                                                                                                                   <–PS-Poll 
                   
                                                       ACK–>
                                                       QOS Null Data–>
                                                                                                                   <–ACK

The default  silent_client.frame_fail_threshold varies from “8 – 30” depending on the Firmware version on the system and this can be changed with the help of AP Boot script. However, before any changes i would advise you to get some tips from Experts.

 

 

My Troubleshooting experience with 802.11 Beacon Frames.

Wireless Frame Analysis involve understanding what to look for in the 802.11 packet. Here lets look at “Beacon” Wi-Fi Management frames and those Interesting packet fields that can come handy while you troubleshoot client connectivity and performance issues caused by beacon frames.

802.11 management frames enable stations to establish and maintain communications.

The following are common 802.11 management frame subtypes:

802.11managementframes

#Beacon Frame:

The access point periodically sends a beacon frame to announce its presence and relay information, such as timestamp, SSID, and other parameters regarding the access point to radio NICs that are within range. Radio NICs continually scan all 802.11 radio channels and listen to beacons as the basis for choosing which access point is best to associate with.

 

beacon

The  Beacon frame has some information that we could glance through.

Section 1 : Physical Header of a Beacon: The radio tap header information are basically pseudo-header to supply additional info from driver to userspace.

And I use wire-shark to decode the packets for analysis and sometime it also depends on how best the software decodes the Wi-Fi packets for analysis. Rarely you might get to see some issues on the protocol analyzers that fail to decode the information right. we might need to double confirm with another (It just happens in corner cases)

The following are few information we have in physical header

*The signal strength

*channel (frequency)

*data rate of the packet

Section 2 : MAC Header and Frame Control of a beacon frame

Following information’s are available in  MAC-LAYER.

*Type of fame

*sub-frame type

*Frame control Flags

*Source address of the frame

*Destination address of the frame : FF:FF:FF:FF:FF:FF(Broadcast)

*BSSID

Section 3: Beacon Frame Body

Following information’s are available in  frame body of Beacon frame.

*Beacon Interval

*capability information: Support for APSD, BLOCK-ACK

*SSID parameter

*Supported rates

*Country Information

*RSN Information

*HT Capability

*Vendor Specific attributes

Wi-Fi troubleshooting with Beacon Frame:

1.)Beacon Miss : I have experienced issues where client missing to hear the beacons would cause them go for repeated frequency scanning and re-association request or disconnections. Some clients are so sensitive that missing 3 or 4 beacons will cause a disconnection and few other survive till 7 too.

You might need to analyse the AIR traffic to see if AP sending out beacons at regular interval or if the beacons getting corrupted in Air or if client receives a corrupted frames.

In such cases try to plot a IO graph in your Wireshark application and/or enable the column DELTA TIME  in Wireshark, which ever is your choice or if both. I prefer to use IO output(this can be further more customized during the Tshoot). NOTE: Getting the exact/close enough problem time frame is key thing.

IO Graph:

The Below sample graph shows you the total traffic on AIR captured VS Beacon (IN RED)send out by AP for a given time.

IO_Beacon

Y-axis represents number of packets and X-axis shows with respect to the time interval.

Default beacon interval time on most vendors are usually every 0.1024 second.

2.)Wifi signal strength identifier: If you get to sniff the traffic staying as close as possible to the client machine , you get to see how well the client can hear the SSID(signal strength). [ considering comparing receiving sensitivity of the sniffing adapter and client NIC ]. Then by Looking at the signal strength parameter you can tell if the client is connected to far away access point or having week signal.

This will help mostly to isolate issues such as network coverage holes especially for engineers who is validating the network from remote.

3.)Date rate: Looking at the rate Beacon is sent out, you can tell if lower data rate has been disabled or not. Since Beacons always sent out @ lowest rate (base rate) configured on the Essid. Also the supported rate parameter in the frame body gives you information at the lowest rate the data packet(QoS data) will be send.

4.) BSSID parameter on the Beacon will tell you which AP the beacon belong to. So you get to know how far the AP is away from the user(if the capture is taken close to the user). NOTE: BSSID is unique to an AP.

Unless the wireless infrastructure is a single channel architecture where all the APs will share the same BSSID on a given radio.

5.) If you want to know whether if the AP supports or advertising its support for WMM, Fast BSS transition support , you should be able to find that by looking at the beacon frame.

6.)RSN information on the Beacon frame will tell if the SSID is secured or open. This field is critical for a wireless client to identify if they are connected to open network or secured network and after the wireless layer 1 association(I like to call this as Layer-1) if client need to send out a DHCP packet(Layer-3) or it has to perform layer 2 authentication further like MAC-AUTH/MACHINE-AUTH/DOT1.X before layer 3.

Seen following cases in field:  On a beacon frame RSN bit is set for a captive portal SSID(incorrect behavior of AP a software bug) causing the client connection issues. While in the same environment Macintosh laptops were able to survive this issue while the other IOS devices couldn’t and they were not able to associate to Wireless network.

7.)Beacon frame carries information about the AP vendor and even the AP chipset vendor in use.

Its been helpful for me adding some useful column’s such as “DATE RATE , SIGNAL STRENGTH, CHANNEL, RETRY, DELTA-TIME” in Wire-shark application during my packet analysis.

You can always add more packet list column preference that will help your packet analysis.

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