Questions tagged [packet]
The packet tag has no summary.
83 questions
2
votes
1
answer
129
views
Nested VPN connection via Wireguard
I designed the following topology:
Client A -> Server B -> Server C
Server C: wireguard server that NATs packets from its clients (in this case just B) before sending them to the Internet. Its ...
- 151
0
votes
2
answers
134
views
ubuntu arp problem with who-has x.x.x.x tell y.y.y.y
i have a single server which two VM(ubuntu) configured as ubuntu-edge(with frr module for routing - wan side) and ubuntu-fw(for lan side), between these machines there is a virtual internal interface. ...
- 1
2
votes
1
answer
1k
views
How to mark packets by program
How to mark all packets (inbound and outbound) for specific program/ cmd in Linux using iptables or any other firewall/ tool
Given that --cmd-owner option was deprecated ref:http://www.spinics.net/...
- 63
0
votes
1
answer
1k
views
How to retrieve raw bytes of DNS response?
I want to retrieve raw bytes of DNS response for debugging reason, for example:
dig -t https clickhouse.com
;; ANSWER SECTION:
clickhouse.com. 242 IN HTTPS 1 . alpn="h3,h3-29,...
- 10.6k
1
vote
1
answer
302
views
Why does adding a counter queue to my Netfilter chain break my VM?
I'm configuring Netfilter Tables to queue packets to and from the userspace, and the table configuration I have so far looks like:
table inet filter {
# protocols to allow
set ...
- 23
2
votes
1
answer
2k
views
Error when trying to corrupt packets in linux terminal (netem)
The following rule corrupts 5% of the packets by introducing a single bit error at a random offset in the packet:
sudo tc qdisc change dev ens8 root netem corrupt 5%
But recently it gave me the ...
- 123
0
votes
0
answers
872
views
Why are packets being dropped (kfree_skb)?
I am currently sending ~9mpps, each packet is 72bytes large, and is a UDP DNS request. The packets are being sent to a Dell server I have using an intel i40e interface. The server is using all of its ...
- 732
0
votes
0
answers
243
views
New install of Linux Mint 20.2 Cinnamon (5.0.4) has ~50% packet loss - Caused by router?
I have recently installed Linux Mint 20.2 Cinnamon (5.0.4) (Kernel 5.4.0-74-generic) on my desktop on a separate drive from a Windows 10 install. On Linux I noticed very inconsistent connections when ...
- 43
1
vote
0
answers
1k
views
Can't find kutil after installation of krb5-usr
I need to merge keytab files and all tutorials mention kutil. But I can't find it:
root@nfsserver:/etc# kutil
bash: kutil: command not found
But krb5-usr is already installed:
krb5-user is already ...
- 161
3
votes
1
answer
4k
views
Package pre-installation script subprocess returned error exit status 1
I have question similar to this one
dpkg: new pre-installation script returned error exit status 1
I'm getting error same as above when trying to install PacketTracer 7.3.1. I think I declined EULA. I ...
- 133
1
vote
1
answer
585
views
Why is it that TCP packets can be modified to block invalid packets, but not UDP packets
On a random day I was googling iptables rules to harden my desktop, and came across this post[1]. At some point the guide mentions blocking invalid TCP packets using tcp-modules with these rules;
...
- 266
1
vote
1
answer
848
views
ncat stops listening after 100 UDP packets
I'm continuously sending packets to a UDP server after 1 second. To listen for UDP packets:
ncat -klup 1234 --sh-exec "cat > /proc/$$/fd/1"
However, after printing 100 packets, nothing else prints....
- 113
0
votes
1
answer
2k
views
Why specify packet size during ping test?
Does it make a difference to specify packet size during ping tests (RedHat)?
Engineers in my company asked for ping checks with packet size of 2000 bytes (-s 2000). On certain systems, this fails, ...
1
vote
2
answers
5k
views
How to check if a packet reached an interface in a multi-interface context?
Consider the following topology:
I am sending ICMP (ping) packets from host B to 10.0.1.1. They reach the target and the target answers with a reply. The connectivity works fine.
When running, on ...
- 1,663
1
vote
1
answer
589
views
How to avoid forwarding ports?
I am doing UDP socket programming in C. In order to listen to a port, I need to forward ports in my router. My question is how to avoid doing that and still being able to communicate over the internet,...
- 33
1
vote
2
answers
628
views
Maintain destination port of TCP packets after leaving through another local port
problem:
I have an application sitting on a host (let's call it host1) that sends TLS-encrypted TCP packets to another host's port 5015 (let's call it host2). Due to network restrictions, the host1 ...
- 123
1
vote
1
answer
3k
views
iptables: transparent tcp traffic proxy
problem:
I have a TCP server and client that each listen on port 9000. I have the server and client deployed on two different hosts where traffic can only pass through port 80 between them. I want the ...
- 123
7
votes
1
answer
20k
views
How to get metrics about dropped traffic via iptables?
We are using iptables firewall. It is logging and dropping various packages depending on its defined rules.
Iptables log file entries look like:
2017-08-08T19:42:38.237311-07:00 compute-nodeXXXXX ...
- 919
0
votes
2
answers
193
views
How does FreeBSD handle installing 2 packages which share a common dependency?
I'm working on FreeBSD 11 and already using programs with tcpdump as a dependency, which has libpcap and libsmi as dependencies.
I want to also install tshark, the console version of wireshark. I'll ...
- 1,311
5
votes
1
answer
12k
views
IPTABLES: process a packet locally and send a copy to another host
I have a trouble configuring iptables to do this: some clients send messages to a server. I want that the host server processes the messages locally (host A, as normal) but that additionally for each ...
0
votes
2
answers
2k
views
Packet sniffing with TL-WN722N
I've recently started to follow a lecture about wireless network, and I bought an external wifi card called TL-WN722N from TP-LINK to use it for packet sniffing.
I tried to use it in a Kali Linux ...
lapinousexy
16
votes
4
answers
15k
views
How to capture all incoming packets to NIC even those packets are not belonging to me
AFAIK, the NIC receives all packets from the wire in a Local Area Network but rejects those packets which their destination address is not equal to its ip.
I want to develop an application that ...
- 263
1
vote
1
answer
2k
views
How to capture traffic from an entire website (including external servers) using tcpdump
I was wondering if its possible to capture all network traffic coming from a single website using tcpdump. I am interested in capturing the sizes of all incoming and outgoing packets from and to a ...
- 133
3
votes
1
answer
118
views
Remote control alarm
I want one of machine have a remote control alarm running that can be triggered by any remote machine. More precisely
Machine A is running the service in the background
Any remote machine B can send a ...
- 5,288
1
vote
0
answers
118
views
How to open a changing file with wireshark?
Given a pcap file that is being created in the background, e.g
tshark -w out.pcap > /dev/null &
How can I open the changing file with wireshark
wireshark -r out.pcap
Does nont work
