All Questions
157
questions
2
votes
0
answers
307
views
How can I use the "location of socket in memory" field in /proc/net/tcp
I'm working on a proxy for linux(C++) that, amongst other functions, keeps track of tcp connections and associates them with the process's pid. To do that, I get the inode in /proc/net/tcp and then ...
1
vote
1
answer
2k
views
What is it happening if a port is constantly (since one or more days) in FIN_WAIT1?
I've a problem when I try to communicate with a server.
If I use the command line:
netstat -np 10.aaa.bbb.12
where 10.aaa.bbb.12 indicates the server address; I obtain an extract with the ...
- 123
0
votes
1
answer
320
views
Limiting nginx requests based on port
Is it possible to drop excessive connections on per port basis?
Let's say I 've multiple virtual hosts in Nginx listening on different ports. I want to set different rules for different ports.
For ...
- 1,335
1
vote
1
answer
3k
views
Using lsof and fuser I can't find the process listening on a strange port
I've read other posts about finding the process ID and what's listening, but sadly couldn't get my issue solved. So, apologize if I missed some info about it.
Running netstat I found a port that I ...
- 13
2
votes
1
answer
722
views
What does a suspended TCP process in linux exactly do and do not?
Regarding TCP connections using NetGui (and wireshark for analyzing):
I set a TCP connection between two PCs using the command nc -p 11111 etc... for the server, and the corresponding one for the ...
- 35
1
vote
0
answers
119
views
Linux doesn't close TCP connection after change a Wi-Fi network
There is some TCP connection between some device behind NAT (Wi-Fi router) and server, located in Google Cloud, both under Ubuntu 16.04. When I changed a Wi-Fi network, this device keeps this ...
0
votes
0
answers
385
views
Why is my TCP connection attempt via PHP acting weird?
I'm not sure if this is better here or on SO but since the issue isn't in the programming I figured it applies here (or on U&L or on serverfault, but I guess/hope I'm fine on here).
I want to ...
- 2,505
2
votes
0
answers
1k
views
Need help figuring out a random connection timeout issue on a server
I discovered this issue trying to loadtest a custom node.js websocket server, where some sockets are failing to connect (they hit the connection timeout). It does not appear to be related to the ...
- 121
1
vote
1
answer
6k
views
How to immediately kill orphaned TCP connection?
Closing orphaned TCP connections is surprisingly difficult in Linux. This issue has been raised here, here, here, and here; however, neither of the approaches worked for me.
Calling close() doesn't ...
- 131
2
votes
1
answer
712
views
how to open tcp connection in fish shell
I am looking for a way to open TCP connections in fish shell.
In bash, I can do the following to open a TCP connection. This is quick telnet type test when telnet is not installed.
$ echo > /dev/...
- 13.8k
2
votes
1
answer
2k
views
Which protocols (TCP or UDP) consume more %CPU?
I'm sending data from the client to server using IPERF3, fist I used TCP and then UDP. I observed that maximum time TCP consumed more %cpu than UDP. Generally which one suppose to consumed more %CPU? ...
0
votes
1
answer
101
views
OpenVPN doesn't forward HTTPS traffic, HTTP works fine
I have an OpenVPN server running on a Raspberry Pi, and I'm encountering issues trying to connect to HTTPS sites using it. I can connect to HTTP sites (confirmed via nc example.com 80). From the ...
- 2,485
0
votes
0
answers
82
views
in Debian server, IPTABLES PREROUTING behave differenty for different ports
I have following three rules in my iptables firewall
-A PREROUTING -i eth0 -p tcp -m tcp --dport 12346 -j DNAT --to-destination 11.207.2.4:12350
-A PREROUTING -i eth0 -p tcp -m tcp --dport 12348 -j ...
13
votes
4
answers
40k
views
How to send binary data in netcat to an already established connection?
I can do the following to send binary data in netcat:
echo -e '\x80' | nc host port
But I don't want to do it like this, what I want is to connect to a server:
nc 192.168.1.115 12345
And then send ...
- 131
1
vote
0
answers
4k
views
How to make tcpdump display only source IP, destination IP, ports and timestamps
I am running tcpdump to track traffic on 2 interfaces, one input and one output. The sole purpose is to measure the latency between the time when the input interface receives incoming TCP traffic and ...
- 249