Questions tagged [tcp]
TCP stands for Transmission Control Protocol and is one of the core protocols of the Internet Protocol Suite. TCP complements the Internet Protocol (IP), and therefore the entire suite is commonly referred to as TCP/IP.
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Force windows to communicate to specific ip addresses via specific network card
Hello I'm currently facing issues with tcp communication on a windows 10 system with two network cards.
I need to connect specific hardware which is in a LAN.
Sometimes windows uses the network ...
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What is the correct way of shorten this nat based multiple ports?
Can these rules shorten to single line:
post-up iptables -t nat -A PREROUTING -i vmbr0 -p tcp --dport 3050 -j DNAT --to-destination 192.168.1.3:3050
post-up iptables -t nat -A PREROUTING -i vmbr0 -p ...
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What is the source ip dest ip source mac and dest mac in Gratuitous ARP response
So I am sitting at host A. And I need to send Gratuitous ARP response to Host B. in Gratuitous ARP response I dont know the mac address of Host B my computer on LAN. But can I add 0xFFFFFFFFFFFF to my ...
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Finding Public Ip Address of security camera
I have installed my home security camera and it's run on 192.168.192.2 localhost and is accessible through android apps. But I would like to know what the public IP address of this camera is so I can ...
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Outgoing TCP traffic redirection
I have a program that attempts to communicate with an old server on the 1.1.1.1:5555 (for instance) using TCP. The problem is that I no longer have access to that IP (my new server works on 2.2.2.2:...
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Open shells with ncat on wan target
I created an azure VM and I configured a ngrok server to make my localhost accessible from internet and I put a VPN to VM in order to simulate a wan attack.
What I want is to set a TCP connection to ...
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why might nmap on a computer be reporting port 443 as closed on some but not all computers?
When I run nmap event-bridge.twilio.com on roughly half the computers in my network I get this:
PORT STATE SERVICE
443/tcp closed https
When I run it on the other half of the computers in my ...
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TCP window probe
I was referred to this site when originally asking in the Networking SE.
I have a few questions about rwnd advertisements in TCP. I have read the RFC but was left with unanswered thoughts (or maybe I ...
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How is an IP address assigned to a process in TCP?
When TCP connection is established between two sockets, suppose that there are multiple NICs in the computer, so which IP address will the socket bind [ or - which IP address will be passes into bind()...
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Why don't we have a usable IP address in 127.0.0.0?
From theory, each part of an IP address is a number between 0 to 255 (256 usable slots in total).
But why is 0 not used in any IP addresses in their 4th part and they always start from 1 in IP ...
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Botched TCP wrapper remotely; how can I connect? Haste is needed
I am trying to help a colleague connect locally to a linux machine (I believe Debian), which uses TCP wrapper for security.
I ssh'd onto the computer and tried to give him access by clearing the ...
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Nobody listens on port, yet something accepts connection on it
Here is some background information first, although it may not be relevant to the problem.
I am learning Kubernetes and I set up a cluster where pi-hole runs as a service. I can access the admin ...
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Packet loss on a single Windows 10 machine in the network
I am having this issue where one of my computers keeps freezing the transferences between any of the nodes of the network.
It runs on Windows 10 Enterprise 10.0.19044.
Packet Loss
Intermittent ...
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Is it possible that FTP makes any bit error?
I have been thinking so far that FTP deosn't cause any bit errors while transferring files. But recently, I met a problem that the files I sent through FTP between my two servers are sometimes ...
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Retransmission in less than one second
On my Linux machine I use nc to communicate with a echo server running on my android device. I use nc to send text to port 65303 of the android device. After entering test1 the same text is sent back ...
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Why does my internet connection only work properly with a UDP-based VPN?
My house is connected to the main router in another building via a single LAN cable that is run partially underground, partially outside (along the wall of the house). There is one switch on the route,...
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Where is the iptables MARK location in TCP package?
In my CentOS7 Server, I emptied all the iptables rules, and then add below rule:
iptables -t mangle -N DIVERT
iptables -t mangle -A PREROUTING -p tcp -m socket -j DIVERT
iptables -t mangle -A ...
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unable to establish TCP connection with server (Java)
I have been trying to connect to my own Java TCP application, which is running on a rented server with static public IP.
Scenarios that work:
server runs host app, and servers from https://check-host....
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What is the corresponding TCP states for states in iptables? (NEW and ESTABLISHED)
The iptables manual says
ESTABLISHED meaning that the packet is associated with a connection which has seen packets in both directions, NEW meaning that the packet has started a new connection, or ...
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How can I assign an ephemeral port range to a specific linux service and not the entire IP stack
For example: If I want sshd to listen on 22 but use ephemeral ports of tcp 50-60 for communication.
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Relay TCP upload traffic and make download traffic go directly to the client
This is a supplement for iptables SNAT for UDP rule is only applied to some traffic
In fact, I have three machines:
the client
the target server
the relay server
What's my motivation for doing this?
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bitcoin-cli testnet : Could not connect to the server 127.0.0.1:8332
I've installed bitcoin-cli from here
I run the bitcoin core on Ubuntu 20.04 (AWS EC2).
mac-os also experiences similar problems.
Ubuntu 20.04 screen capture for the error messages
The commands I've ...
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Meaning of IPTABLE duplicate values
I'm new to IPTABLES and when I execute the following command
/sbin/iptables --list -n | grep 16381
I could see multiple entries as shown below :
ACCEPT tcp -- a.b.c.d 0.0.0.0/0 ...
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How do computers know how to use TCP
I'm asking from a Windows perspective but any perspective is great.
Are NICs all a computer needs to interface with TCP? Wouldn't they also need some sort of software associated with TCP, or is that ...
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What ports range is safe from taking by Windows 10
I wrote small program and I would like to use some TCP ports. Same ports for a longer period of time. The problem is each time Windows 10 wakes up it makes its mind which ports to reserve for its ...
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is TCP handshake handled by web application flask or web servers like nginx?
if I run a simple flask application in development mode(so web server and web application is the flask library) on port 5000. is there a way to see SYN, SYN-ack, ack requests that are exchanged ...
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Sending PJlink commands with netcat
I have a projector that I want to control over TCP using a protocol called "PJlink", but I can't manage to get it working. I'm currently trying to do this through Windows Terminal in WSL ...
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Block outgoing connection from server to Internet, but enable specific TCP port access from outside
I am using Mikrotik RouterOS on a Mikrotik router.
There is a server in my network from which every outgoing connection using every protocol should be disabled. I achieved this with a following rule:
/...
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Server hello is not returned without SNI
I've setup a proxy server (squid) with https_port enabled. When I send requests to this server using a url like domain.com or even using a host alias (i.e. manually written in /etc/hosts), there's no ...
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Terminated HTTP/2 connections on macOS in Inea ISP
We’ve had a discussion about my issue on Reddit, but I wanted to try here too.
I have a symmetric 300 Mbps fiber connection at home and sometime in September/October 2021 I’ve started seeing weird ...
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