Questions tagged [packet-capture]

Packet capture is the act of capturing data packets crossing a computer network. Packet capture can be: Deep packet capture (headers & payload), or partial packet capture (headers only).

Packet capture is the act of capturing data packets crossing a computer network. Deep packet capture (DPC) is the act of capturing, at full network speed, complete network packets (header and payload) crossing a network with a high traffic rate. Once captured and stored, either in short-term memory or long-term storage, software tools can perform Deep packet inspection (DPI) to review network packet data, perform forensics analysis to uncover the root cause of network problems, identify security threats, and ensure data communications and network usage complies with outlined policy. Some DPCs can be coupled with DPI and can as a result manage, inspect, and analyze all network traffic in real-time at wire speeds while keeping a historical archive of all network traffic for further analysis.

Partial packet capture can record headers without recording the total content of datagrams. This can reduce storage requirements, and avoid legal problems, but yet have enough data to reveal the essential information required for problem diagnosis.

Source: Wikipedia.

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Ntop monitoring - Hosts visible with no SPAN/mirroring

I am attempting to use ntop to monitor traffic over a Cisco Catalyst switch. I was assuming that in order to see any of the traffic, I'd have to use monitor, as described here:…
Cory J
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Ifconfig result on the server running PF_RING with zerocopy

I have an application which uses PF_Ring zero copy as a part of its packet sniffing capability. When this application is running would it be possible to find out the amount of RX/TX traffic using ifconfig or is it correct to say that ifconfig does…
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Disabled all TCP Offloading and still get 65Kb packets

I'm capturing packets in a Tensorflow two-node training. I want to capture the packet sizes over the wire (< MTU) from the hosts. Because of that, I turned off all of the offloading with ethtool. This is the output of ethtool -k : Features for…
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How to see contents of output queue of NIC in Linux and introspect frame delay

I am experimenting with tc tool to implement prioritization of specific data coming from my computer and would like to see exatly how the frames are scheduled and how much time they spend in the qdisc queue before the transmission (before being…
Hadarelv
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Forwarded Packets are received by namespace's veth0 but not received by application

I use libtins (It uses Pcap) to capture link layer packets and forward to a network namespace where the actual application runs on. Client(Browser) -> Server -> Pcap -> Pcap Send -> br0 (Bridge) -> Namespace -> Application Now, I see that the…
sqlbie
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How can I capture traffic for a daemon listening on a cloned loopback IP address?

I have a daemon listening on a virtual IP address attached to a cloned loopback interface (lo1) on FreeBSD 11.x. Inbound traffic for that daemon could arrive on several different physical interfaces, however running tcpdump on loopback only shows…
Alnitak
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OpenVPN log connections per user

I'm trying to set up a VPN solution where I can log packet captures of individual connections. I've been focusing on using OpenVPN but I am amenable to other solutions. It is important to note that I have a limited amount of developers to support,…
ahjohnston25
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Loopback interfaces is not pinging on both pcs for packet tracer

I am trying to ping my isp ip address (aka loopback 1) and loopback 10 to PC1 and PC2. Whenever I ping both ip addresses and default gateway from pc1 to pc2 it works. However, when I'm trying to ping my isp ip addresss (1.1.1.1) and loopback 10 ip…
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How can I gathering Network Traffic on AWS?

I am building packet mirroring using the Linux type's iptables tee module. In the case of instances(EC2), we confirmed that promiscuous mode can be set on AWS console configuration. than, I wonder if it's possible to use promiscuous mode on…
scott
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CentOS 6 - Find KVM VM with HW addr

We are running KVM VM's (Linux & Windows) on our CentOS 6 & 7 hypervisors. Sometimes we are noticing a lot of packets going in or out. Now I want to see which IP address or network adapter causes this. I use iptraf to see the in & out rate of…
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Tips for working with very large pcaps?

What is the best approach for working with very large collections of network traffic (500GB+)? Specifically, I'd like to be able to filter packets which match various payload and protocol criteria (e.g. all TCP packets to port 1111 with the string…
pavja2
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Network sniffer that work as windows service

We need to log the traffic of incoming traffic for some application on our server. The first instinct is to use Wireshark and of course, as soon our remote session end Wireshark also shutdown. Since we need to capture the data over a long period of…
Lishi
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Are TCP RTO value and RTT value influenced by the packet size?

I am doing troubleshooting in my network. I found some re-transmission by using wireshark. The segment 1400 bytes are well transmitted but The segment 800 bytes are lost and re-transmitted. I know RTO value is controlled by RTT and its variance. My…
nimdrak
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How to turn an ethernet port into a passive listener?

I want to capture ethernet packets with my raspberry pi's ethernet port. I know I could create an ethernet bridge between two ethernet ports on the raspberry and analyze the packets internally with tcpdump. But I need the entire thing to not rely on…
guerlando
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rpcapd behind a firewall

I have a remote server with rpcapd installed that follows strict security policy rules. Any client can access to the server only via firewall that follows same security policy (please, don't blame me, it wasn't my idea). The only port opened on the…
enzo
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