commandline packet analyzer

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12
votes
3answers
9k views

Can I monitor a local unix domain socket like tcpdump?

I'd like to monitor responses on a unix socket without disturbing the original connections and pipe them to a script for processing. I know how to do this with tcpdump for tcp connections but I ...
8
votes
1answer
4k views

How can I diff two network dumps from tcpdump or Wireshark?

I'm having a problem with one of our customers' embedded computers. They seem to discard some network packets which they should not. I can capture the TCP communication from a managed switch outside ...
5
votes
5answers
20k views

Practical Tcpdump examples? [closed]

I want to collect tcpdump examples, as many as possible! E.g.: how to filter FTP passwords on eth0; OR how to filter HTTP 404 errors, etc.
5
votes
1answer
2k 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 ...
5
votes
1answer
619 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 ...
4
votes
2answers
5k views

How to make tcpdump (or other tool) to actually dump TCP stream?

I expect something like this: $ nc example.com 80 GET / HTTP/1.0 HTTP/1.0 500 K.O. Content-Type: application/null Content-Length: -1 $ Meanwhile: # tcpdump -i eth0 --actually-dump-all-tcp ...
4
votes
3answers
43k views

What's all this deploy.akamaitechnologies.com traffic?

I happened to do a tcpdump while leaving my Mac idle, and when I came back after a mere half-hour there were something like 5000 packets involving deploy.akamaitechnologies.com, in which my computer ...
4
votes
3answers
4k views

How to capture last N seconds of packets using tcpdump

How can I capture the last N seconds of packets using tcpdump?
4
votes
1answer
275 views

understanding the tcp header

The first 16 bits in a tcp header, (rfc793), are for the source port, right? The next 16 are for the destination port. When I run tcpdump -xx I can recognise MAC addresses of boxes on my system. Does ...
4
votes
1answer
2k views

tcpdump filter for given bytes on given position

I'm searching for a way to filter traffic for specific bytes. What I have is a stream that I capture with wireshark or tcpdump. Now it logs way too much, so I want to drop every packet that has 0x23 ...
4
votes
2answers
7k views

tcpdump promiscuous mode on OSX 10.8

By examining my wireless router configuration I can see there's 2 IPs assigned: 192.168.1.100 -> laptop (Macbook Air OSX 10.8.2, where I runtcpdump) 192.168.1.101 -> ipad But then if I run: sudo ...
4
votes
1answer
871 views

How to ssh in the face of huge (25 second) latency?

I need to create an ssh connection between two Linux machines running Centos v5 but the latency could be as high as 25 seconds. I find that if I test something approaching this configuration ...
3
votes
2answers
360 views

Filter packets sent via HTTP to a port other then 80?

I have a database communicating on port 7474 via HTTP (sigh), and I want to debug the queries sent to / from it. However, a filter such as http.request.method == "POST" Filters out every post ...
3
votes
1answer
153 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 ...
2
votes
2answers
468 views

Program to record data transmission between two computers using a TCP port

I am looking for a way to view data being transmitted over a TCP port between two computers. Is there a software package that allows this? I suppose I could script something to re-route data coming ...
2
votes
2answers
1k 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
2answers
3k 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 ...
2
votes
2answers
407 views

Is there a serious issue with setting the SUID bit on tcpdump?

I'm running tcpdump on a remote machine, and piping the output to Wireshark on my local machine over SSH. In order to do this, I had to set the SUID bit on tcpdump. For background, the remote machine ...
2
votes
1answer
109 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
4answers
882 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 ...
2
votes
1answer
451 views

Using tcpdump on displayed TCP data

If sudo tcpdump -i eth0 -X gives me tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes ...
2
votes
4answers
5k 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
3answers
319 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, ...
1
vote
2answers
400 views

How to quieten tcpdump output when reading a pcap file?

I notice that when using tcpdump to read a pcap file, the tcpdump command somehow manages to print information to my console even when I redirect both STDOUT and STDERR. How can I prevent tcpdump from ...
1
vote
2answers
32 views

Can tcpdump be instructed not to report packets to a specific source?

I would like to monitor packets using TCPdump. Sadly, I must do this remotely - in this case, I'm using a remote desktop from VNC, but at best I can do it over SSH. What I mean by "at best" is: I am ...
1
vote
2answers
143 views

Different packet sizes on Wi-Fi and 3G interfaces while tethering

I am using an application called android-wifi-tether on a mobile phone. My laptop is connected to the phone over Wi-Fi and the phone is connected to Internet over 3G. I am using tcpdump to sniff ...
1
vote
1answer
750 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
235 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 ...
1
vote
1answer
1k views

How to set NIC in promiscuous mode on mac book air?

I am trying to run my nic on MacOSx at promiscuous mode and then use tshark / tcpdump Option1: ifconfig en0 promisc but I get this message: ifconfig: promisc: bad value Option 2: I tried sudo ...
1
vote
1answer
405 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 ...
1
vote
1answer
757 views

TCPDUMP -G option

Can anyone give me examples of the TCPDUMP -G use with 60 seconds as a example and incremental files? like : tcpdump -w %s -G 60 i try it but don't increment files only reset the file each ...
1
vote
1answer
717 views

Log all http and https traffic that goes to the router in OSX

My router has ip 192.168.0.1. How can I log all the traffic it receives under http and https(port 443)? I think using tcpdump should do the trick but I'm not sure how to run it
1
vote
2answers
1k views

Count exchanged bytes per TCP connection

I need to get a table updated with the exchanged bytes (Rx and/or Tx) for each ESTABLISHED TCP connection on a linux machine (well, at least, a list of connections (port ranges), thus not actually ...
1
vote
0answers
44 views

What's wrong with this tcpdump syntax?

sudo tcpdump -i ath1 -s 0 -nne "(type mgt and subtype beacon)" Can anyone help me? I was following a tutorial at http://wiki.secarmour.com/2013/09/capture-wireless-traffic.html but seems I got ...
1
vote
2answers
113 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 ...
1
vote
0answers
214 views

how to sniff from a TP-Link ADSL modem?

I have a PC and a tablet that connected to a TP-Link ADSL modem. PROBLEM: I want to see the packets that send and receive from my modem not my PC( to see both wire and wireless packets) I search ...
1
vote
0answers
112 views

No response received from github ssh randomly

My git pull started to stop working randomly with this error $ git pull ssh: connect to host github.com port 22: Connection timed out fatal: The remote end hung up unexpectedly I tried debugging ...
1
vote
0answers
160 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 ...
1
vote
0answers
390 views

latency measurement on Linux-based router using tcpdump

I am using tcpdump to measure latency on a linux router, i.e. the delay experienced by packets as they pass through the router (made of Ubuntu 10). For this purpose, I captured packets in the IN and ...
1
vote
2answers
609 views

How can I monitor which applications make DNS requests on OS X?

I'm trying to send all of my unencrypted day-to-day traffic over an SSH tunnel, which is working pretty well with a simple SOCKS proxy. Skype still goes outside, but that's okay, as Skype is ...
0
votes
2answers
1k views

Why are some tcp packets with the RST flag classified as new incoming connection?

While looking through my iptables log, I keep observing periodically incoming connections with the RESET flag being set from a few ip addresses within my ISP's network. This is a sample tcpdump on one ...
0
votes
1answer
476 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
2answers
2k views

tcpdump - just packet data

When using tcpdump, how can I print just the packet data? For example (anonymized): sudo tcpdump -X 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' ...
0
votes
2answers
2k views

TCPDUMP: are these args consistent or meaningless together?

I'm using tcpdump on routing software, and trying to check whether the presence of ip/ip6 protocol with an ip6/ip host (i.e., the other IP family), or else specifying a mix of IPv4 and IPv6 IPs as ...
0
votes
1answer
427 views

Detect HTTP sessions using tcpdump [closed]

I have a tracefile and I want to find all web servers that were successfully visited in the trace, contacted via HTTP. I'm using: tcpdump -r file.trace - tcp port 80 Maybe I have to search for a ...
0
votes
1answer
45 views

Why does tcpdump not come precompiled and how to compile it?

Hello I recently downloaded tcpdump from the www.tcpdump.org/ website, extracted the tar.gz file and found nothing but source and header files, I do not posses the necessary knowledge to get a working ...
0
votes
1answer
30 views

tcpdump prints nothing while trying to listen communication with sip server

The following command sudo tcpdump -nqt -s 0 -A -i eth0 port 5060 works and prints incoming SIP messages. Now I want to see entire communication and entering the IP address of the SIP server: ...
0
votes
1answer
138 views

Captured packets with tcpdump vs. tcpdump > file

Why is there such difference in number of packets captured by tcpdump when the output is written to console and to file? $ tcpdump ... 1681 packets captured 1681 packets received by filter 0 packets ...
0
votes
2answers
647 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
2answers
983 views

Trouble with mergecap [ concatenation of pcap files ] - undesired info in output file

I hope somebody will be able to help me... The problem is with merging multiple .pcap files. Recently - like a week ago I've used a mergecap to merge mutiple pcap files into one. Everything worked ...