Tagged Questions
is a data communications endpoint for exchanging data between processes executing within the same host operating system.
1
vote
0answers
54 views
+50
Local unix socket - rough idea of throughput
Is anyone aware of throughput benchmarks / measurements for using a local unix socket for inter-process communication?
I want to illustrate the performance benefit of having a local database ...
0
votes
0answers
28 views
SSL handshake fails when connecting using websocket secure(wss)
Hello I am trying to connect to a websocket (wss) . Its ssl handshake fails .Below are the apache logs, it would be very much appreciated if somebody can share some light on this .
proxy_util.c(2213):...
0
votes
0answers
7 views
how to connect Maxima cas via shell socket port?
I am new to Linux. I was installed maxima-5.38.1 in my kubuntu os. Calling the maxima via php shell execution. Its working perfect. But I was search with help of maxima found with maxima port ...
2
votes
1answer
44 views
TCP: One PC can connect to other's listening port but not vice versa
I have a local network (doesn't really matter if it's VPN or real local network - I've tried both).
One computer running Linux Mint opens a socket with
mint$ nc -l 4242
And the second one running ...
0
votes
0answers
21 views
Linux C programming to get Client IP always get 0.0.0.0 [migrated]
When i try to get client IP,I always get 0.0.0.0 when program running in CentOS,But when the some code running in Ubuntu,It will get the right IP :127.0.0.1
I don't understand that's why.
Please ...
0
votes
0answers
34 views
uwsgi nginx , problem with accessing socket file on ubuntu --> 502 bad gateway error
I'm running into some permission issues with uwsgi and nginx running on Ubuntu 14. I get a 502 bad gateway error.
I'm logged in as root but top -c tells me that uwsgi is runned as www-data (don't know ...
3
votes
0answers
43 views
TCP/IP relay from one client to multiple clients
I'm looking for a linux tool to run under fedora that will open a tcp/ip socket for listening, let it connect multiple clients on the same port. Then when one client sends a message relay it to all ...
1
vote
0answers
17 views
Port Forwarding, Render Console Warning — Rails v4.2.6
Forwarded port on local router 192.168.1.4:3000 to allow public access w/ my IP address.When viewing my rails app @ http://47.145.229.103:3000/ everything displays correctly, but theres a console ...
0
votes
1answer
47 views
What network interface is a process using?
Is there a way to find what process is using a given network interface? The title of a related question on here is a bit too specific for my needs.
I need to confirm whether my process is running on ...
2
votes
1answer
125 views
Disable TCP packet processing by Linux Kernel on a specific port
I'm working on a TCP/IP stack, that currently runs from Linux user space using raw sockets.
To test this, I need to disable the Linux Kernel TCP code for a specific port, so that the kernel doesn't ...
1
vote
1answer
114 views
How do I list all sockets which are open to remote machines?
A vanilla ss -l lists (on my current machine) lots of open sockets, with various Netid types and many of which are only listening on localhost.
How do I get a list of all and only those sockets ...
1
vote
0answers
41 views
Incoming packet does not delivered to socket
I have a vpn application that connects to vpn server with a tcp socket. I have marked tcp socket packets with setsockopt and SO_MARK. I can ping vpn gateway ping 10.0.0.1 successfully.
Then I try to ...
6
votes
2answers
64 views
How to limit range of random port sockets?
There's a binary that I need to run which uses bind with a port argument of zero, to get a random free port from the system. Is there a way I can constrain the range of ports the kernel is allowed to ...
1
vote
1answer
31 views
inflight sockets in linux
I was checking code of sendmsg system call for AF_UNIX socket, there I find one function: wait_for_unix_gc ( a garbage collector of inflight sockets).
Can anyone brief what these inflight sockets are?
...
2
votes
1answer
81 views
Properly remove sockets accidentally created with tmux
I just started using tmux; out of muscle memory (was a screen user) I tried to create a new session like this: tmux -S mySession, and after I detached, a socket named mySession= appeared in my working ...
4
votes
2answers
115 views
Is there a way to identify the PID (or cgroup) of a socket without iterating through all the processes in /proc/
I need to identify the cgroup of a process given the socket. Specifically, I have a process on the same machine that is calling my process using tcp, and I need to identify the process or its cgroup. ...
1
vote
0answers
31 views
How to get rid of getting into Vim when using web shell?
I created a web shell using Python socks. Actually that's is just a web shell and not like SSH connection.
It can let people run program in the background and output STDOUT and STDERR the same time. ...
0
votes
1answer
162 views
why linux reuse 'time_wait' port?
As I know, tcp port in 'time_wait' stat cann't be used. However, in my experiment, server reuses the 'time_wait' port? Why?
Firstly, in client machine, type command ehco 40000 40001 > /proc/sys/...
0
votes
1answer
92 views
How authentication is done between two nodes in tcp/ip or udp client server socket
I have a client socket program and server socket program in C TCP/IP . I execute the server program first on a port say 5000 and then executes client program on the same port and then server respond ...
4
votes
2answers
284 views
What's the difference between “>&1” and “>/proc/self/fd/1” redirection?
I'm working on some script that being run by rc.local at startup, and I noticed that output redirection works quite strange.
If I write something like echo "foo" >&1, it ends up in syslog, and ...
0
votes
1answer
48 views
Ping through a specific Ethernet port
I am using RHEL 6.4, I have teamed two Ethernet ports (eth2 and eth3). I am trying to test the connectivity, I mean I want to test whether the eth2 and eth3 are working or not?
One way is to disable ...
3
votes
1answer
153 views
unbind port of crashed program
is there any way to unbind a port that was previously binded by a program that crashed at some time?
I don't like to reboot the development-machine every hour.
0
votes
0answers
54 views
How to recover a screen session?
I'm running a screen session and it seems it hung up somehow.
0 ✓ user@hoster ~ $ screen -ls
There are screens on:
30418.pts-2.hoster (Detached)
1 Socket in /run/screens/S-user.
However, when I ...
1
vote
0answers
85 views
strace for troubleshooting inter process communication
I have output captured by following command:
strace -f -e trace=process,socketpair,open,close,dup,dup2,read,write -o rsync.log rsync -avcz --progress src/ dst/
it is a bit long so I've uploaded it ...
0
votes
0answers
27 views
Ensure that file socket is already opened
I'd like to open a simple file socket that can run in background like:
nc -l -k -m 10 -U my_socket -c cat &
so other processes can connect into it with nc -U my_socket -c read.
After this ...
0
votes
0answers
22 views
PAM: make dbus listen to some address
I'm new with PAM and have some questions about it. Is possible to make PAM configure dbus, and make dbus listen to some address?
1
vote
1answer
88 views
How to bind (or remap) a socket with an abstract name to a path?
In our system (Linux 4.4) we see a a unix socket with an abstract namespace (those starting with @ with no corresponding file on the file system). Showing its details with lsof reports:
serv 7539 ...
1
vote
1answer
212 views
Udev rule setting up SocketCAN socket only works correctly only when run manually
I want to start slcand (the userspace daemon for the serial line CAN interface driver) when my Lawicel CanUSB dongle is plugged in. I followed Pascal Walter's step-by-step guide and all seems to work (...
8
votes
1answer
152 views
Why doesn't file redirection to and from a named pipe work, but piping to cat does?
This is a simple echo server in Unix, using nc:
mkfifo fifo
cat fifo | nc -k -l 4458 -v | cat >fifo
(based on this)
As I can see it, the data flow works as follows:
fifo (my named pipe)
|
| (...
2
votes
1answer
197 views
why do I find (under /proc/pid//fd) sockets with broken symlinks
I don't think they're closed, because I would expect that after a close() the fd would disappear, but I see a bunch of lingering fd -> socket[xxxxx] entries with broken symlinks which don't seem to be ...
2
votes
1answer
165 views
Blocking a specific external IP:Port connection in RedHat?
I know that in RedHat, in the IP tables I can block incoming connections to a local port. I can also block connections from a specific IP.
But is it possible to block a connection from a specific IP ...
1
vote
0answers
20 views
Several TCP Window Scale values depending on interface?
Is it possible that TCP Window Scale value set by default on a socket (not raw) depends on the interface used?
Where are these values stored?
1
vote
1answer
86 views
How do I get active unix domain sockets for a specific pid if I can't use lsof command?
If I have no permission to use lsof, how do I get them for a process with pid already known? Thanks
I know netstat -l -p command print out active unix domain sockets, but it seems it's not updating ? ...
1
vote
1answer
361 views
How to pass received data from netcat to another script as argument?
I have simple bash nc script:
#!/bin/bash
nc -k -l 127.0.0.1 4444 > filename.out
which listens 4444 port for TCP connection. Instead of redirecting received data to filename.out I would like, if ...
2
votes
0answers
63 views
Implications of increasing igmp_max_memberships
I am writing an application that will subscribe to 150+ multicast groups. It appears the linux default number of multicast subscriptions is 20 which can be increased via
sysctl -w net.ipv4....
1
vote
1answer
143 views
Where to put socket so PrivateTmp can be true
I have a C++ program which must communicate with other services (including httpd), and does so via a socket in /tmp
With the advent of systemd and the PrivateTmp=true setting, processes like httpd ...
2
votes
0answers
277 views
Netlink access inside a network namespace
I'm trying set up an IPsec gateway (strongSwan) on a Raspberry Pi 2.
The Pi was already providing a number of services on the LAN using a private IP address.
My initial attempt to turn it into an ...
5
votes
0answers
191 views
Sharing unix sockets across unprivileged lxcontainers
I have two unprivileged containers and I'd like to share a unix socket between them. Each container has its own user on the host, complete with separate subuid and subguid mappings.
I've tried ...
3
votes
0answers
14 views
Limit access/transmit rights on NIC to a single user application
I currently have a RT patched linux machine and I need to have full and undelayed access to my Wired interface card. I am running a realtime non-preemtable user application which sends a couple of ...
0
votes
0answers
143 views
espeak, alsa Unknown PCM
I have a Debian Wheezy and I connected to my linux a USB Dac.
I use every time a MPD server (and that work)
Now, I would like to use espeak with pyttsx
But when I start my script (It worked and my ...
-1
votes
2answers
133 views
shell command wrapper for socat
I have used the command
socat - foo
The text I type is sent directly to address foo.
Is there some general-purpose wrapper for stdin (along the lines of ! from ed) that lets one parse a shell ...
2
votes
1answer
105 views
When is a port considered being used?
I am getting port in use cannot bind on process restarts. I am trying to find out when a port is considered being used?
Is it only when in LISTEN mode?
Can it also be if a connection is open to the ...
1
vote
1answer
257 views
Socket remains ESTABLISHED even if remote process is stopped
I am running a celery - rabbitmq configuration between a client and a server. The client process opens a connection on the server at port 5672. Using netstat -np on the server I confirm that since the ...
11
votes
2answers
280 views
What is the difference between &6 and /dev/fd/6?
To read from file descriptor 6 I can use <&6 or </dev/fd/6 (aka /proc/self/fd/6). Usually both work equally well. However if that file descriptor happens to be a socket, strange things ...
1
vote
1answer
164 views
How to provoke a broken pipe
I try to debug a python script that interfaces MPD using python-mpd2.
When the script tries to perform an action after being idle for a couple of hours, it terminates with an exception (...
4
votes
1answer
197 views
root cannot connect to symlinked socket of other user
I use oh-my-zsh's ssh-agent plugin to have a static symlink to my current SSH_AUTH_SOCK created. When connecting through SSH with agent forwarding enabled the file /tmp/ssh-agent-$USER-screen is ...
5
votes
0answers
958 views
OEL6 Slow boot && Millions of socket files in /tmp/orbit-gdm
Background on question
Lately I've been having some trouble with slow booting on the servers, sometimes over 2 hours to boot stuck on "Enabling Local Filesystem Quotas:"
After searching I managed to ...
2
votes
0answers
84 views
how to list all the epoll requests in linux
I used to use netstat for displaying all listening sockets. How can we list epoll requests on the sockets? Or is there anyway to dislay epoll requests using netstat?
2
votes
1answer
126 views
Time synchronization, use NTP or just socket?
I am using a PC and a raspberry pi(both run Linux) to gather sensor data, raspberry pi gathers laser scan data, PC gathers image captured by camera. I must synchronize time for these two machines. I ...
0
votes
1answer
51 views
strace vs web browser
I was trying to strace an iceweasel like this:
strace -e trace=connect iceweasel
And I was expecting to see calls to connect when I load new pages. Surprisingly, there weren't any.
Why so? Am I ...
