Questions tagged [wireshark]

For questions about Wireshark, a packet analyzer

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DORA process TCPIP [duplicate]

http://www.tcpipguide.com/free/t_DHCPGeneralOperationandClientFiniteStateMachine.htm I'm reading through the entire Discover, Offer, Request, Acknowledgement phases in DHCP. And I am really confused. ...
0 votes
1 answer
48 views

In wireshark, why following a TCP or UDP stream does not remove ICMP packets?

In Wireshark, when I follow a TCP or UDP stream using right click -> Follow -> UDP Stream, if there are some ICMP packets from same endpoints, wireshark will keep them in the stream. Why? Since ...
1 vote
1 answer
272 views

DHCP packets in a Wi-Fi network (WEP2-Personal)

The DHCP packets with the message type Discover, Offer, Request and Acknowledge use the L2 broadcast address for communication (even in the Acknowledge packet which has an IP destination of the newly ...
3 votes
1 answer
13k views

Wireshark Ethernet II trailer field?

What does Trailer field stand for in Ethernet II frame? Can you explain this on following cases (length of ARP packet is 28 bytes)? Case #1: Ethernet II Destination: Broadcast (ff:ff:ff:ff:ff:ff) ...
2 votes
2 answers
677 views

Capturing dot1q packets with Wireshark on a PC

I have spent the last few hours trying to capture some trunk packets so I can see and examine the dot1q VLAN field. I have tried mirroring the trunk port to my PC using the following commands on Cisco ...
0 votes
0 answers
43 views

TCP blocked until the acknowledgment received

I am currently facing an issue in my application where the TCP messages seem to be blocked until an acknowledgment received. Specifically, the subsequent messages wait for the acknowledgment of the ...
3 votes
2 answers
24k views

Ethernet frame IG/LG bit explanation - Wireshark

I have a screenshot of an ethernet packet frame from Wireshark. I need to explain what is the meaning of these marked lines (with dots and zeros). I searched in web, but still I don't have an answer. ...
0 votes
1 answer
270 views

Wireshark filter for specific SYN packet which never received a SYN/ACK

Is there a way in wireshark to find out a single SYN that does not get answered by SYN/ACK?
0 votes
0 answers
20 views

RPCAP active mode usage or deployment example

This is in reference to https://www.winpcap.org/docs/docs_40_2/html/group__remote.html, the RPCAP protocol. Wireshark (on Windows) has support for connecting to passive mode deployment. And the RPCAP ...
0 votes
0 answers
38 views

Can TCP seq number increment after sending a FIN?

I have an embedded device connecting to a server (on AWS Application ELB if that matters). Both the server and the client are instructed to close the connection after one request. I noticed that the ...
0 votes
1 answer
460 views

Why am I not capturing any ICMP packets on wireshark?

I am doing a lab where we are meant to ping an address and use wireshark to capture ICMP packets when we ping that address. WHen I run the wireshark capture with the ICMP filter on and ping my address,...
0 votes
1 answer
325 views

How to determine which TCP payloads should be combined to form a complete PDU?

I understand that the TCP itself provides a byte stream connection, but has no idea nor does it care what its payload is and how it is segmented to fit into individual packets that travel on the wire. ...
1 vote
1 answer
8k views

Wireshark not capturing packets?

I am trying to use Wireshark, but for some reason it won't capture packets. I've used it once before and it worked just fine, so I can't understand why it's not working right now. The only thing I've ...
0 votes
2 answers
96 views

Does ARP play any role when we try to access a website?

I was looking to find the role of ARP whenever say we want to access a website like google.com. I found some answers here. But, when I tried to use Wireshark to check the ARP request I wasn't able to ...
3 votes
1 answer
72 views

Wireshark - how to merge packets of Data of a bin file which was sent over the LAN?

I tried to send a ~80k dat file over the LAN from one device to another and then combine the captured packets back to the original file, for testing and learning purposes. I couldn't find any way to ...
1 vote
1 answer
131 views

Does Wireshark capture all Wi-Fi traffic under the same access point even with WPA encryption?

I know that free unencrypted-Wi-Fi is dangerous since all the traffic in the same AP is visible. Does Wireshark capture all Wi-Fi traffic under the same access point even with WPA encryption?
0 votes
2 answers
248 views

How to include in the filter http requests satisfying the given condition and the respective responses?

For example, I want to see all the http requests containing the given string in the http.host field and their respective responses. Right now my filter is frame.number < 61403 and http.host ...
2 votes
0 answers
72 views

Average bits/s report in tshark

Does tshark has an option to report average bit/s statistics of the capture which appear in Wireshark at the end of Statistics > Capture File Properties? I'm trying to automate a load test and need ...
5 votes
2 answers
7k views

What is the difference between tshark, dumpcap and others for collecting/sniffing traffic?

Wireshark provides tshark and dumpcap, and I've also seen people using the wireshark binary or even tcpdump to collect/save network traffic. Online it is claimed that tshark or dumpcap hardly make a ...
2 votes
1 answer
800 views

Wireshark capture showing a TCP packet with no flags [closed]

In our network, I captured a TCP packet by Wireshark that has no flag set. What is the meaning of such packet ? Here is the dissection in text format : Frame 1: 54 bytes on wire (432 bits), 54 bytes ...
2 votes
1 answer
110 views

Is there a way to precompile data from pcap to speed up booting wireshark?

Is there a way to precompile/precalculate the data from a pcap file to speed up booting wireshark? I have a big pcap file and wireshark is crashing when I try to open it. I know it sums and computes a ...
1 vote
3 answers
246 views

UDP encrypted packets

I am analysing a Wireshark capture as part of understanding UDP/TCP, DNS and HTTP concepts and how packets are sent. I found an interesting sequence of messages in the Wireshark file, but I am not ...
9 votes
1 answer
10k views

ARP request with unicast MAC?

Regarding ARP requests, I got to believe that the destination MAC address was in all situations the broadcast address. Yet I got across this Wireshark capture: I just cannot understand the 3rd ...
5 votes
1 answer
1k views

How to disable TCP window scaling in Wireshark?

I am currently using Wireshark version 1.12.2. When I searched the internet I found this result (source: wireshark.org) But, this option is not available in my version. I could see only the "...
0 votes
1 answer
111 views

Wireshark -Protocol Hierarchy Omitting large amount of subprotocol traffic

Based on responses, I've repositioned this question to ask why the subprotocols under my TCP header are not accounting for the sum of packet transfer. (I.E TCP= 97.1%, remainder of packet content not ...
0 votes
1 answer
136 views

Where are the characters in Wireshark's Packet Bytes pane?

I've just updated my Wireshark to version 4.0.1, and now, while investigating a TCP communication, I don't see any textual information anymore in the Packet Bytes pane, as you can see from this ...
0 votes
0 answers
362 views

Monitor UDP packet in wireshark

I am trying to monitor udp packets from server to client in Wireshark at both end. Can I get any clue in Wireshark with which I find out that ok this specific udp packet is what I sent and received at ...
0 votes
1 answer
50 views

Wireshark: Internet Control Message Protocol

I've installed Wireshark on my Windows machine, and to my knowledge, the section at the bottom represents the packets in their octal and ASCII form. When I click on the IP version & the header ...
1 vote
1 answer
55 views

troubleshoot pcaps for BACnet industrial protocol in OT/IoT

I have a test bench that I am trying to learn how to take pcaps with WireShark for BACnet UDP traffic of building automation devices. 4 devices in total on test bench: Windows 10 OS running ...
0 votes
1 answer
369 views

Wireshark: Cannot find frame type of packets

I am getting used to Wireshark operation and currently, I am investigating different frames (control, management, data frame) and using filter in these links (https://mrncciew.com/2014/10/02/cwap-802-...
0 votes
2 answers
942 views

Monitoring comms between 2 devices on a switch using Wireshark

I am new to networking and now learning wireshark now and unable to capture comms between 2 devices. This is my setup. When I connect to "Ethernet" (Ethernet is the Ethernet port at my PC) ...
1 vote
1 answer
581 views

Does Ethernet have a header and a trailer?

I have read that Ethernet have a header and a trailer, but in Wireshark I can only see an Ethernet header and no Ethernet trailer.
1 vote
1 answer
782 views

What is "cflow" in ipfix?

I am learning ipfix and found a cmd like this: tshark -r ipfix.cap -n -d udp.port==4379,cflow -O cflow What does the cflow part mean here? I was also told to filter cflow if I use Wireshark in ...
0 votes
1 answer
169 views

Wireshark only shows single HTTP request instead of its constituent TCP packets and ACKs

To my understanding, in packet no.39, the post request actually consists of multiple tcp packets getting sent, and they all get acked once by no.40. The server has received it. Now, the server sends ...
0 votes
2 answers
333 views

Determine network traffic on a switch port in bit/s from Wireshark

I am trying to understand how much data is flowing through a specific port on a Cisco (Stratix) switch. I have set up Port Mirroring so that I can capture the traffic on the target port via Wireshark. ...
2 votes
2 answers
110 views

Loops in routers-same packet?

Considering a loop topology between a few routers with a host connected to one of them, when it's default routing directs to the cycle. Even when observing Wireshark, how can we know its the same ...
1 vote
1 answer
1k views

How does wireshark calculate the TCP length when there is no header indiciating such?

In wireshark, you have this field: [TCP Segment Len: 1380] # How is this calculated? My assumption is using the IP headers plus TCP's. TCP Segment Len = IP Total Length - IHL - TCP Header Length In ...
0 votes
1 answer
59 views

What does this Wireshark capture filter do

I was reading through a guide where I saw the following Wireshark capture filter used. (tcp[2:2] > 1500 and tcp[2:2] < 1550) I had a brief look over Wireshark's website which listed their ...
0 votes
0 answers
12 views

ARP Header's Mac Address set to 0 when broadcasting [duplicate]

I'm learning about Ethernet frames and networks and Wireshark has been very useful. I have a doubt regarding broadcasting and ARP request, since we don't know the Target MAC address, in the ARP's ...
0 votes
1 answer
80 views

Wireshark on ProCurve 1810G - IEEE802a protocol

I have recently started a networking course and acquired an old HP ProCurve 1810G-24 Switch to play about with, which I have updated to the latest firmware. I'm using Wireshark to monitor the traffic, ...
0 votes
1 answer
75 views

Unwanted Wireshark Optimizing Received 802.11 Channel for Frames

I am trying to run an experiment which involves monitoring 3 wireless channels simultaneously in Wireshark which would allow me to see a single frame captured 3 times on each channel. To do this, I ...
0 votes
1 answer
425 views

Probe Request getting\understanding Information Elements (IEs)

I'm trying to read Information Elements (IEs) from the probe request can't seem to understand the stracture of it as I undersatnd it size can be 0-2312 bytes but how do I know how many there are? I ...
2 votes
1 answer
617 views

Wireshark not showing Frequency/Channel

I am using Ubuntu 18, and wireshark-gtk. I followed this and this tutorials to create a column named/showing frequency/channel. But all the packets I captured have no frequency/channel showing.I tried ...
3 votes
1 answer
268 views

Wireshark Decrypting IKEv1 Text PSK to Hex

I'm trying to debug a Cisco VPN setup as part of a Uni Lab (so please don't worry about posting of keys etc. it's just a toy setup with no internet facing connection). I want to decrypt the IKEv1 ...
6 votes
3 answers
45k views

How to view MTU size in Wireshark?

I've been reading about maximum transmission unit (MTU) which is the size of the largest protocol data unit (PDU) that can be communicated in a single, network layer, transaction. I'm generating a ...
6 votes
2 answers
632 views

TCP Flow-control questions that drives me mad

This is a capture of a TCP session when I was downloading the 10Mb file from an FTP server. The server has an ICW of 10x MSS, so this means that the server can initially send 10 segments without ...
0 votes
0 answers
17 views

Some random client requests fails with unexpected TCP [RST] packets [duplicate]

I have a service doing listen that serves clients over a TCP sockets connection with a raw binary protocol. The principle is basic: the connection is established, the client sends a request with data, ...
1 vote
1 answer
47 views

what are scenario where re-transmission packets can been seen in wireshark logs

While troubleshooting i came across this challenge ,able to see retransmission packets continuously in packet capture . please let me know in what scenarios this retransmission packets are seen.
0 votes
1 answer
137 views

Homeplug av frame

I want to check differences between a frame sent by a pc connected to an homeplug and one pc connected directly with the gateway/router. When i sniff packets i cannot see any differences in the frame, ...
0 votes
2 answers
225 views

Detecting Ethernet over power by packets

If someone plugs an Ethernet over power (EOP, Homeplug) into the switch and then connect elsewhere in the building, can I detect this device by sniffing the packets with tools like Wireshark or ...

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