1
vote
2answers
28 views

tcpdump: how to get grepable output?

I am trying to troubleshoot an issue where I only have tcpdump available on an appliance. I want to use tcpdump to filter web traffic, and only display traffic containing certain strings. I do the ...
0
votes
1answer
93 views

Why does tcpdump take so long to read pcap files?

I am using a third-party tool that captures network traffic as a pcap file during a network test. When I attempt to play these files back, I use the tcpdump tool with the -Aq -r options, and pipe the ...
0
votes
0answers
99 views

OpenVSwitch no traffic on bridge

I setup a bridge(br-int) with OpenVSwitch and plugged in eth3 which is connected to a hub. When other computers send traffic on this hub, I can get those traffic on eth3. However, if I try to do that ...
0
votes
2answers
460 views

how to use tcpdump to capture all packets on local network?

I have a home used wireless router, one linux laptop and android connected to it. Lets say the linux has ip 10.5.5.1, mac AA:AA:AA:AA:AA:AA and android has 10.5.5.2, mac AA:AA:AA:AA:AA:AB. The ...
0
votes
1answer
26 views

Is there a way to limit number of packet captures with tcpflow?

I want to limit the number of captured packets, such as: tcpdump -c 20 I want to use tcpflow instead. Is this possible? The console throws a syntax error using tcpflow with the -c parameter. edit - ...
0
votes
0answers
233 views

Can't telnet: TCP connection doesn't get established

I am having issues with telnet from a machine. TCP connection is not getting established. SYN gets sent out and SYN_ACK comes back but not sure why the ACK is not getting sent back. I am guessing ...
1
vote
1answer
166 views

How to detect packets that are only from the local network and not from the ISP/internet?

I'm building a bandwidth monitor using JNetPcap(java version of libpcap/winpcap). I need to recognise packets within the home network so that I don' count them towards the total bandwidth used. I ...
0
votes
1answer
559 views

have tcpdump show the 'conversation' as i would get from wireshark?

Is it possible to get the same output i would get from: tcpdump port 80 -w log.pcap wireshark log.pcap in wireshark Analyze > Follow TCP Stream and then in the bottom drop down Entire ...
1
vote
2answers
167 views

Check if HTTP calls are gzipped

Assuming that I have an application server (Linux) running on port 80, how can I make sure (with tcpdump, I guess) that all incoming requests are gzipped and all responses are gzipped as well? Also, ...
2
votes
1answer
93 views

LAN assembly 2 packets into 1 packets?

I have two computers A and B, there is a TCP connection between them. I use TCPdump to capture the packets. I notice that when A sends a lot of TCP packets to B, each IP packets are 1514 bytes. In ...
2
votes
2answers
2k views

tcpdump error: no suitable device found in Linux

Guys im trying to test a tcpdump to google.com (im new to Linux by the way). so here's what i typed in my shell: $tcpdump src 192.168.1.xxx and dst www.google.com and port ftp but i get this ...
1
vote
2answers
2k views

how to make tcpdump to display ip and port number but not hostname and protocol

I'm using tcpdump for some tests I want to see the IP and port number but the output of tcpdump is like IP pl1snu.koren.kr.http > kitch.pl.sophia.inria.fr.dnp: Flags [P.], seq 54:72, ack 1, win ...
1
vote
1answer
553 views

Record multicast stream on multi-homed Linux host

I have what sounds like the simplest possible use case, and yet nothing is satisfactory. I have a multi-homed host and I would like to listen to multicasts on eth1, and shove all the payload (NOT ...
1
vote
1answer
352 views

What does this tcpdump printout mean?

I'm not very experience with networking, so on my free time, I usually try and learn some more things about the internet and how it works. While at school, I came across tcpdump and wanted to give it ...
0
votes
1answer
413 views

How do I capture 802.11 headers on an AP while not in monitor mode?

I am wondering if it is possible to extract 802.11 frames on a router running OpenWrt operating as an access point. I tried using tcpdump and loading the dumped packets in Wireshark, but I could only ...
4
votes
1answer
1k views

Traffic between VirtualBox guests not showing up in tcpdump

I have a test environment setup with 4 VirtualBox guests running CentOS 6. Each has one network device attached to a bridged adapter, which is my primary network connection on my PC, with a static IP ...
2
votes
1answer
129 views

How to output a simple network activity plot in console in Linux?

There's tload that plots load average. There's iftop that network usage as bars. How to do something like this: # tcpdump -i eth0 --plot 'host 1.2.3.4' 13:45:03 | | 0 in 0 ...
1
vote
0answers
157 views

tcpdump loses connection

I'm on Ubuntu – but it's the same on Debian. I'm using tcpdump in order to track the connection of computers on my private network. At some point, the internet connection of the computers launching ...
2
votes
2answers
799 views

Why can't I see other computers' traffic in the output of tcpdump?

On LAN, when I use tcpdump on my eth0 interface to monitor packets, nothing happens although other computers are using the internet. It is only when I begin to use internet by visiting a website ...
2
votes
4answers
798 views

capture local network traffic

I have a PS3 and I am going to capture the PS3 traffic. However, how can I capture it with wireshark? Because when I capture it, it only shows the traffic to my computer only. For example, PC ...
5
votes
1answer
539 views

Linux interface stops receiving packets as seen by tcpdump

I have a linux box with two interfaces: eth0 is a builtin and eth1 is a USB-LAN. There is an IP configured on eth1. eth0 is up but no IP is configured. This interface is used for sniffing with ...