All Questions
30
questions
5
votes
1
answer
19k
views
Windows 7 firewall causing remote connection to time out; should refuse connection
The Windows 7 Firewall is running with default options to allow outbound connections and block incoming connections. I have a process trying to connect regularly from within my local network, which is ...
- 53
5
votes
2
answers
7k
views
Detect what outgoing ports are bypassed by firewall
My school has a firewall which limits most outgoing ports. There're only TCP/80, TCP/443, TCP/21 allowed. Is there's a way to find out all the outgoing port allowed by the firewall?
My current idea: ...
- 2,667
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?
- 143
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 ...
- 133
2
votes
1
answer
6k
views
using iptables to prevent RST related to a specific port
I have a program which uses libpcap to capture incoming TCP SYN packets, these SYN packets are destined for a specific port.
But I have no tcp listening socket for that port, so in practice, the OS ...
- 3,055
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
1
vote
1
answer
86
views
Where do I start to troubleshoot this strange activity from my firewall?
I noticed that my firewall yesterday blocked outgoing attempts starting at port 61494 and worked its way up to 62381, making a TCP outgoing attempt at each port once. The remote IP address seems ...
- 131
1
vote
1
answer
3k
views
How to listen to all ports (udp and tcp) or make them all appear open in Debian
I got an external Debian server. The problem is that my university campus doesn't allow connections to go outside when the port is different than TCP port 22, 80, 443, or UDP port 123. I tested them ...
- 63
1
vote
1
answer
3k
views
RPC Connection Filtered with no Firewalls
I have a workstation (PC1) that cannot communicate with a domain controller over RPC (TCP/135).
C:\PortQryV2> portqry.exe -n 192.168.1.1 -p tcp -o 135
Querying target system called:
192.168.1.1
...
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
0
answers
212
views
Firewall : Is inbound required for getting response while Outbound rule already there?
I developed one MVC web application which have Web APIs and hosted in Amazon Instance and one windows application for calling those APIs for getting response from that server.
Both Web and Windows ...
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 -...
- 11
0
votes
3
answers
1k
views
What typically uses port 44380?
A company just asked me to open port 44380 in my firewall so that their software could work.
This made me wonder... what is the customary use for port 44380?
- 15.8k
0
votes
1
answer
1k
views
TCPview: Some strange process?
I just install the TCPview to check if there are any abnormalities in my computer connections, and there are something looks strange:
There are 2-3 process that show the following status from time to ...
- 101
0
votes
1
answer
413
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