Questions tagged [tcp]
The Transport Control Protocol (TCP) is a low-level part of the protocol stack used by the Internet. It sits directly above the IP layer and is responsible for making sure that dropped packets are resent.
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Checking if service is running, Service is installed already
So basically i installed an Automation Anywhere product in Amazon Linux 2, when i checked the
netstat -tulnp | grep LISTEN
i didn't found the Listener that's supposed to be there exist. Thus leading ...
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Why is `ss --kill` so slow?
I've measured ss --tcp --numeric --no-header --kill dst 1.2.3.0/24 on various machines (all running Ubuntu Server 22 or 24 LTS) and it consistently needs around 7-10ms to complete. Any idea where the ...
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Parallelization of TCP Stack in embedded Linux
I have a ARM Cortex-A9 dual-core processor running with 800MHz. An yocto based embedded Linux with kernel 5.15 (will be updated to 6.6 soon) is executed on the ARM processor.
When I transfer data ...
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Netstat -an command output TCP [::]:135 [::]:0 LISTENING
In my InfoSec course assignment, we were given the task to analyze the different communications that were displayed when we run the command netstat -an. While analyzing I saw the following ...
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Possible issue with tcp_tw_recycle causing TCP connection failures
I am experiencing an issue where a Linux server sometimes does not respond to TCP connection requests with a SYN-ACK packet. I have a traffic capture showing a successful connection followed by a ...
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Iptables rule with per-connection and per-packet conditions
For example, I have 2 conditions for passing in iptables (input chain): destination tcp port - condition 1, source mac address - condition 2
Is it possible to create the rule or some rules, that will ...
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Bitwise constructs to match TCP flags in nftables
I can't find any documentation that would explain the syntax and evaluation of the following sample constructs:
add rule filter output tcp flags & (syn | ack) == syn | ack
add rule filter output ...
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How can I have multiple TCP clients connected to server ttyS0?
I'm trying to test following envirorment:
One server (it's a router, It has busybox and few other cmd) with a a physical serial port and and open socket
#tcpsvd -v 0.0.0.0 -p 999 cat /dev/ttyS0
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How to Log Each Outbound TCP Connection
At my company we have a set of 3 identical VMs. These VMs house an app that "sends messages". The app sends each message by making a TCP connection out to one of two fixed IP addresses (...
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TCP RST doesn't reach process running inside Podman container
I'm debugging an issue I'm seeing where connections between a podman container and the host aren't being closed inside the container.
I've written very simple test programmes: server and client.
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Why receiving TCP network packets require more memory bandwidth and CPU utilization than transmitting packets?
I am analyzing an ARM system with Linux kernel 5.15 running. I am running iperf3 to measure the network throughput between two ARM systems.
Note that these are simulated systems and are loosely ...
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TCP out-of-order and GRO feature with linux kernel 5.14
according to the RFC9293, the PSH flag will be set in the last TCP segment created from the buffer (Ref. https://datatracker.ietf.org/doc/html/rfc9293#name-send).
I'm in a scenario where the traffic ...
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stdin redirection from /dev/tcp/localhost/port
I'm trying to get my head around some TCP-related topics, and have been experimenting:
The following works fine:
Process A: nc -l 12345 | wc -c
Process B: </dev/random head -c 1k > /dev/tcp/...
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ARM-LINUX-GCC with LIBMODBUS
Hi everyone, I'm trying to compile a program using "arm-linux-gcc" with "libmodbus";
however it seems the compiler is not set up for libmodbus.
What should I do to fix it?
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How to protect a docker container with tcp wrappers, xinetd or something like that?
I have a Dicom medical docker container, on a bridged network, that receives tcp connections (not web/http/https) from other Dicom enabled devices, such as MRI scanners. It is an old DCMTK binary ...
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