All Questions
157
questions
0
votes
1
answer
673
views
Sniff tcp connection and forward to TCP connection on other adapter
I have a system with two network adapters. One of the network adapters is connected to a port mirror, so it sees all the traffic in the network. I'd like to sniff that connection for a certain TCP ...
0
votes
1
answer
88
views
Attack on a Linux file server | What is the damage of this file contents?
TCP Networking
This file was uploaded using a loophole in a file uploading network program I was writing. The ability to access the server itself was too simple and the techniques I used resulted in ...
- 11
-3
votes
1
answer
83
views
Why does my IPTables changes not deny access from all IP addresses except CloudFlare’s ranges?
I am running apache on ubuntu 18.04. I used IPtables to deny access from all IP addressed except CloudFlare’s ranges and when I run iptables -L –line-number I get
1 ACCEPT tcp – 131.0.72.0/22 anywhere ...
0
votes
1
answer
466
views
Samsung Smart TV UA43N5300ARLXL/UA43N5300ARXXL unable to connect to internet over UFW firewall
I have a home network with a Raspberry Pi at the center running Pihole and UFW. The Pihole is both the DHCP as well as DNS server.
Ever since I started using Pi Hole I've not had any issues until ...
- 21
1
vote
0
answers
2k
views
SSH fails to connect from one computer but works from other computers
Problem
I have an external VPS server running Ubuntu 18.04 with openssh-server 7.6p1. I can connect via ssh to this server from many different networks except from one particular client. This ...
- 111
1
vote
2
answers
2k
views
Packet reaches OS but not the process
Sorry if my issue is a bit hard to summarize in the title. That is the best I could come up with.
TL;DR Version: How do I debug when packets reach OS, but not the destination process?
Explanation: I ...
- 123
1
vote
0
answers
592
views
How to enable ECN marking in IP header in Linux?
Is the ECN marking in the IP header is performed by default in Ubuntu (4.15.x kernel) or should the kernel be recompiled with a special option? I configured a RED ingress queue at an Ubuntu machine, ...
- 11
6
votes
1
answer
13k
views
Capture only TCP SYN-ACK packets with tcpdump
I'm trying to capture only TCP SYN-ACK packets, i.e. with both SYN and ACK bits set with:
tcpdump -vvvni eth0 tcp[tcpflags] == tcp-syn and tcp[tcpflags] == tcp-ack
but it gives such error:
tcpdump: ...
- 244
3
votes
1
answer
18k
views
Use netcat to listen on a port and send output from a command when a client connects
I have a Raspberry Pi (Debian Linux) connected to my LAN that can read data from some connected devices and output it to STDOUT.
Let's say the program is run on "Server" and I want to serve the ...
- 135
0
votes
0
answers
273
views
log tcp contakting connection with nftables
I Want to log TCP contracting Connexion using nftables(iptables)
I tried to write tcp flags in Rule, but when I acces to webpage of destination IP address I get just this Info in my logfile :
...
- 71
0
votes
2
answers
280
views
If I disable iptables its working. Which rule is making my websites a timeout?
I have a VPS with nginx but no website is working and timeout is sent. When I disable iptables everything is fine. But no idea which rule/s is taking the problem. Any help?
$sudo iptables -S
-P INPUT ...
- 1
0
votes
2
answers
592
views
how to run mincraft server on linux
I wish to run minecraft server om my linux mint 19.0, but I have some troubles, I can start it in local, and connect by 127.0.0.1:25565 but i can't run it on my ip in inthernet, 4 example my ip is 2....
- 101
1
vote
2
answers
357
views
Why Imx6q(Embedded Linux Device) ethernet communication is too slow?
I have tried several methods to test the ethernet communication of the Imx6 card.
1) When I ping in my computer from IMX6, the ping does not reach the IMX6. But when I ping to imx6 from the computer, ...
- 11
3
votes
1
answer
2k
views
Create a TCP half open connection with bash command
Is there a way to (easily) create a TCP half-open connection using a bash command with common Linux tooling?
I want to monitor availability of a remote server using such mechanism. I know it is also ...
- 151
0
votes
0
answers
216
views
Iptables configuration
Here is my iptables script. Can it be better ?
Thanks in advance !
#!/bin/bash
#iptables-restore < /etc/iptables.test.rules
iptables -F
iptables -X
iptables -t nat -F
iptables -t nat -X
iptables ...
- 1