All Questions
30
questions
0
votes
0
answers
43
views
Teardrop detected from TCP ACK from myself
I'm experimenting with linux (Debian 5.10) networking to allow me to connect two networks (eg. 192.168.0.0/24 with 172.17.0.0/16) together.
Setup
In my case it is a small server with one NIC, hosting ...
- 126
0
votes
1
answer
337
views
How to send back TCP packets using iptables
I am trying to demonstrate TCP communication with a Ubuntu 18.04 box (which mocks a QNX setup) that does not have a listener installed. Consider that due to some license issues it might not be ...
- 8,457
0
votes
1
answer
2k
views
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:
/...
- 33
2
votes
1
answer
671
views
Why does my virtual machine (Debian on Proxmox) not respond to a TCP SYN of another VM even though it arrives?
I got a very strange problem and I am out of ideas to solve it. I hope anyone over here has a helpful idea.
Some info about the virtual machines:
VM0: Debian 10 - 192.168.10.102 [+ 2 more interfaces]
...
- 41
3
votes
1
answer
1k
views
How to have Windows firewall send RST packet for blocked port
Is there any way to instruct windows firewall to send Reset packets for a blocked TCP connection instead of dropping the packet?
- 1
0
votes
1
answer
467
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 ...
- 93.8k
1
vote
2
answers
757
views
iptables SNAT target and TCP ACK packets
I need to establish a TCP connection where the client is spoofing its IP for all outgoing traffic. My first attempt was to add a rule to the POSTROUTING chain like so:
iptables -t nat -A POSTROUTING -...
- 13
0
votes
1
answer
414
views
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?
...
- 13
0
votes
1
answer
2k
views
TCP communcation - HyperV virtual machine opening port on host
Here's the summary of my fight to connect to a port on the hypervisor host from a VM hosted on the same machine:
Set up in the Hyper-V Manager:
Virtual Switch Settings
Internal
'Enable virtual LAN ...
- 11
-3
votes
1
answer
84
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 ...
- 159k
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
0
votes
1
answer
1k
views
TCP RST when connecting via telnet to the application - Windows
I have an application running on Windows.
The application listens on port 54000.
I can connect to the application from the local machine and it works fine:
telnet 127.0.0.1 54000
Now, I am trying to ...
- 141
3
votes
2
answers
5k
views
Getting a UDP-only VPN to work over TCP
For a project of mine, I'm searching for possibilities to have a UDP-only VPN working over TCP (preferably on port 443 or 80). I have found the following while doing some research:
This is possible ...
- 51
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 ...
- 986
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