All Questions
12
questions
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1
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1k
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Meaning of IPTABLE duplicate values
I'm new to IPTABLES and when I execute the following command
/sbin/iptables --list -n | grep 16381
I could see multiple entries as shown below :
ACCEPT tcp -- a.b.c.d 0.0.0.0/0 ...
0
votes
1
answer
541
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How can I identity which process is sending data to a certain host on Linux?
As per title, I want to figure out the process responsible for certain traffic. I can see the traffic in wireshark, but I don't know which process it is.
Is there any straightforward way to do it? I'm ...
0
votes
1
answer
4k
views
Increase buffer size for a specific socket on Linux
I am using CentOS7 and I have to increase the send buffer size (SO_SNDBUF) on a socket listening on a specific port. The application that has the port opened does not natively support this.
Few things ...
1
vote
0
answers
45
views
understand ss -to4 output for a jdbc connection
My application connects to a database over JDBC, and performs a lot of sequential inserts. There is only 1 JDBC connection opened by the application. As the performance is not as expected, I started ...
- 11
2
votes
0
answers
307
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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 ...
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
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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
1k
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sudo netstat -antp not showing PID
i am testing stuff with sockets and i encountered that strange case :
i coded i very simple tcp server in c, i made it block after accept(), just to see what happen when accepting multiple connection ...
0
votes
1
answer
2k
views
TCP socket buffer for every flow
Does the linux kernel create a buffer for every TCP connection, for example when we have 1000 tcp connections the kernel creates 1000 socket buffer and stores the packets of individual flow on its ...
- 11
5
votes
1
answer
3k
views
How to list socket options of running processes?
Is there a convenient way (e.g. a readily-available command or a program that I can write using standard system calls) to list socket options (e.g. TCP_NODELAY) of an open TCP socket of some running ...
- 463
0
votes
1
answer
2k
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List all open sockets in /dev/tcp/localhost/
Is it possible to list all open sockets in /dev/tcp/localhost/ on a Linux machine?
I want to list all sockets where the following command would return 0:
timeout 2 bash -c "cat < /dev/null > /...
- 127
3
votes
3
answers
242
views
Distinct Proxying for any TCP-related Protocol
I'm not sure what to call it (proxy/redirection/relay), and I am hoping some software or solution possibly exists for linux.
My intention is to be able to listen on a single public facing ip:port (...
- 688