a command line packet analyzer

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1answer
784 views

tcpdump and https

Why following command doesnt grab the packets to faceebook site sudo tcpdump host facebook.com and dst port 443 but next grabs sudo tcpdump host java.com
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4answers
1k views

How to capture images transferred via HTTP?

I have multiple browsers and I want save all images with size more than 30KB and save to specified address. What is best way? listen to tcpdump and read the content, and then save to a file, or use ...
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0answers
185 views

router latency measured by tcpdump increases

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 ...
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1answer
440 views

How to log all domains accessed?

Maybe I could use tcpdump, filter out all non-HTTP packets to reduce disk consumption, and then parse the output looking for domain names. Maybe there is a better solution. Do you know one?
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1answer
9k views

tcpdump: “packets captured” vs “packets received by filter”

We have a script which calls tcpdump -v src host <IP address> and port <port number> >>out.txt 2>>err.txt -w capture.cap on multiple IP-s while the other parts of the script ...
3
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1answer
227 views

sandbox tcpdump under OpenBSD?

From FreeBSD 9.0 tcpdump is sandboxed with Capsicum. Are there any solutions for sandboxing tcpdump under OpenBSD? Just want to secure a running: tcpdump -w output.pcap because it can be only used ...
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1answer
904 views

How to recover a file from a tcpdump?

I use tcpdump -i wlan0 -s 0 dst 192.168.1.200 or src 192.168.1.200 -w output.pcap to monitor for ex.: my HTTP traffic. I upload a .zip file through HTTP. How can I retrieve the .zip file from the ...
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3answers
920 views

using “-vvv” with “-w FILENAME” with tcpdump makes better output?

Does it makes a more detailed output if I use tcpdump -vvv -w FILENAME vs. if I use: tcpdump -w FILENAME or it doesn't makes any sense if I use the "-vvv" when I'm using "-w FILENAME"?
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1answer
2k views

Count in real time the output lines from another output command

I think what I want to do is very easy, but I can not find a way to do that: If I put this command: [root@:Active] tmp # tcpdump -i any -s 65535 host 192.168.1.110 and port 1645 or port 1813 -v -X | ...
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2answers
12k views

How to gather DNS A record requests?

I need to record all outgoing A records on a RedHat PC. I tried using tcpdump: tcpdumpdns=OUTPUT-FILENAME-HERE nohup tcpdump -K dst port 53 -w $tcpdumpdns > /dev/null 2>&1 & It makes ...
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1answer
2k views

iptrace for linux: how can I trace full packet contents?

I normally use iptrace on our AIX servers to get packet traces but have recently found out that this doesn't work for other 'nix systems - namely Centos. Does anyone know what the analog would be? ...
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1answer
647 views

How to read a hexdump byte by byte in bash or awk?

This is the hexadecimal output of an IPv6 TCP packet captured with tcpdump: 6000 0000 0018 0620 0000 0000 0000 0000 0000 0000 0000 0001 0000 0000 0000 0000 0000 0000 0000 0002 *0026 0026 0000 ...
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1answer
2k views

what level of the network stack does tcpdump get its info from?

As I was trying in vain to fix a faulty ethernet controller here, one thing I tried was running tcpdump on the machine. I found it interesting that tcpdump was able to detect that some of the ICMP ...
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2answers
2k views

How to modify the output of tcpdump to be human-readable?

I have a tcpdump command: tcpdump -i wlan0 dst port 80 and ! dst 192.168.1.201 and ! src 192.168.1.201 -vvv -s0 -w proba.txt Which gives the following output: root@SERVER:/tmp# egrep "GET|Host:" ...
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1answer
1k views

How can I run tcpdump from a Python script without AppArmor complaining?

For inconvenient reasons going beyond the scope of this question, I have to run tcpdump from within a Python script. I currently just call subprocess.Popen(['tcpdump', ...) and everything works just ...
2
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1answer
577 views

How to know the number of messages received in a message queue at a point of time

I have a implementation where the hardware dispatches 300 packets every second to a host application through DMA transfer and then to the host application's message queue. When packets are sent at ...
10
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1answer
6k views

Buffer size for capturing packets in kernel space?

Going through the man page of tcpdump, it seems kernel can drop the packets if the buffer is full. I was wondering if: that size is configurable and/or where can I see the size for my distro? From ...
3
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1answer
1k views

Is it possible to capture all network traffic using tcpdump?

I have 3 computers on the same sub-net. Computer A and B are communicating with each other (ping, telnet, etc.). I'd like to see the packets between A and B on computer C. Is it possible to do this ...
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3answers
8k views

How to process/pipe TCPDUMPs output in realtime

If I want to tcpdump DNS requests by clients (on an OpenWrt 10.04 router), then I root@ROUTER:/etc# tcpdump -n -i br-lan dst port 53 2>&1 tcpdump: verbose output suppressed, use -v or ...
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2answers
837 views

Understanding tcpdump output on a linux router

My router has an atm0 interface and a VLAN (atm0.1) interface, atm0.1 has the WAN IP address. When using tcpdump -i atm0, the packets captured are only outgoing packet (LAN to WAN). 05:34:19.504895 ...