The tcp tag has no wiki summary.
-1
votes
2answers
48 views
Is Port 13330 a standard-port?
I saw some programs using the port 13330. What is the meaning of this port? Is this port used by a special program?
2
votes
2answers
534 views
200ms latency between TCP send and tcpdump only with large messages
In our REHL server, latency between application send and tcpdump log is always very large for large messages, about 200 milliseconds (see below 697572-488690=208882 microseconds), whereas latency for ...
2
votes
1answer
79 views
Browser fails to reach any host on Solaris 8
I'm running Solaris 8 on a Sun Ultra 2 connected to a Verizon router. nslookup seems to work (it finds google.com) but the existing browser (Netscape 4.76 - yes - it's very old) fails to reach any web ...
0
votes
0answers
11 views
Can we Bring Up eth1 after removing e1000e modules?
I am trying to setup TCP in RTnet. I am not sure whether its possible. I read that RTnet is not supporting TCP. Is that so?
So now I am trying to setup rteth0 as server and eth1 as client. To setup ...
1
vote
1answer
447 views
Port Mirroring in Fedora?
I have set up an application that listens constantly to a port for network packets, and I would like to create another one that receives the same network packets ( for use as a test bed). Getting the ...
0
votes
0answers
20 views
Socket output from server process disappears when process is run by cron
I'm having a really strange problem that only occurs when a server process is launched by cron. The environment is an Ubuntu 12.0.4 LTS distro running in an Azure VM, with an exposed endpoint to the ...
8
votes
1answer
642 views
Kernel socket structure and TCP_DIAG
I'm working on a software which connects to a Real Time data server (using TCP) and I have some connections dropping. My guess is that the clients do not read the data coming from the server fast ...
2
votes
2answers
27 views
Transfer a TCP connection from one Linux box to another behind NAT?
While experiencing an extremely slow download rate on one of my HTTP connections, I thought it'd be nice if I could just transfer the connection from my PC to an energy-saving home server that shares ...
1
vote
3answers
346 views
rsh runs perfectly in normal user but not in root, very strange, why?
When I run command, rsh localhost pwd as a root
It shows below output.
connect to address 127.0.0.1 port 544: Connection refused
Trying krb4 rsh...
connect to address 127.0.0.1 port 544: Connection ...
1
vote
0answers
37 views
ssh will sporadically hang temporarily on fast connection
I am using Ubuntu 13.04 on my laptop, connected to my router at home. When working from home, I will ssh into the servers on campus, through a vpn, with X11 forwarding.
ssh -X ...
1
vote
2answers
70 views
Checking if I can reach some ports from my computer
Is there a terminal command or something on OSX that I can use to test if I can reach some ports on a remote server?
I know these ports are reachable on that server, because I can access them from ...
4
votes
3answers
68 views
How does the server find out what client port to send to?
As I understand it this is what happens when a client makes a connection request:
The server will be bound to a particular port number. The port number is always bound to a listening process. Since ...
0
votes
1answer
34 views
What are the other congestion control algorithms specially designed for lossy Wireless Networks like LTE and WiMax?
I am trying different congestion control algorithms for getting maximum throughput and minimum delay across my setup for TCP flow.Please suggest other available algorithms apart from
Veno, ...
2
votes
3answers
358 views
Linux Shell Script - Send command over TCP to Sharp Aquos
I'm writing a shell script that needs to send an 8 character string terminated with a x0d to a Sharp Aquos TV. An example is 'POWR1 \x0d' (POWR1 followed by three spaces and LF)
The documentation ...
0
votes
3answers
137 views
How to send an email to myself on the same local machine (tcp port 25)
Does anyone know how to sent email to myself?
I am trying to generate TCP traffic on port 25.
8
votes
2answers
22k views
Orphaned connections in CLOSE_WAIT state
I've got a SLES machine that accumulates TCP connections in a CLOSE_WAIT state for what appears to be forever. These descriptors eventually suck up all available memory. At the moment, I've got 3037 ...
0
votes
0answers
44 views
What could be the possible reasons for bad performance of TCP over Wireless or Sate-lite networks ?
I am running a wireless network having Linux(fedora 17) at sender end.We decided TCP_veno is most useful for my network,so we are using it as default congestion control algorithm.Still, We are not ...
0
votes
1answer
104 views
How to display TCP handshake in Linux [closed]
Hi is there a way to display TCP handshake in Linux? Like for example this WIKI - TCP handshake
Not exactly like the illustration but at least it would show client has sent SYN, ACK, FIN etc
and the ...
0
votes
1answer
50 views
How to connect to port immedeately, avoiding socket_bind(): unable to bind address?
When running a code that is supposed to read from a TCP/IP port I often get the following message (depending exactly what language have been used):
socket_bind(): unable to bind address
I know that ...
1
vote
1answer
124 views
Killing tcp connection in linux
I have some dead connection in one application which is in hanged state if client machine is dead.
->192.168.1.214:49029 (ESTABLISHED)
Is there a way to terminate these option from linux ...
2
votes
1answer
82 views
How to run Different congestion control algorithms in FEDORA 17 ..?
Earlier versions of Fedora has different loadable kernel modules which includes diffrent congestion control algorithms etc at (/lib/modules/"kernel-name"/kernel/ipv4).These are present in the form of ...
1
vote
1answer
66 views
Using Wireshark on Linux to observe coupled HTTP-request and HTTP-respond
I use Wireshark on Linux to observe my HTTP traffic. Other programms like Firefox Live Http Headers show coupled http-request from my browser and http-respond from any server.
How using programs like ...
0
votes
2answers
159 views
Why my Http Proxy doesn't reply [SYN,ACK] after received a [SYN] packet from the client?
I have a http proxy running on Linux (RHEL 5.5), intermittently it doesn't reply [SYN,ACK] packet after received a [SYN] packet from the client. This issue can be recovered by restarting the proxy. I ...
2
votes
1answer
400 views
Why can't I use strace with rsh?
If I run rsh, it works, but prints some strange “Connection refused” messages at the beginning:
$ rsh localhost pwd
connect to address 127.0.0.1 port 544: Connection refused
Trying krb4 rsh...
...
22
votes
1answer
446 views
Why does it take up to several minutes to clean a listening TCP port after a program dies?
If I kill a program that is listening on a TCP port, it takes up to several minutes until the port is reclaimed by the system and usable again. I've seen several Q/A mentioning this phenomenon, but ...
0
votes
0answers
194 views
Turn off TCP checksum offload [closed]
I am programming a linux networking driver. It is almost done. When I ping between 2 PCs, everything is perfect. And then I try to use some TCP/UDP protocols, and the receiver never reply. I used ...
1
vote
2answers
344 views
Why TCP TIME-WAIT State is present at both ends after a connection termination?
I am reading how the TCP states work and especially the connection termination part.
All of the books or online material I read, shows that for the termination procedure these states are followed ...
12
votes
4answers
572 views
TCP dies on a Linux laptop
Once in several days I have the following problem. My laptop (Debian testing)
suddenly becomes unable to work with TCP connections to the internet.
The following things continue working fine:
UDP ...
3
votes
2answers
389 views
Getting current TCP connection count on a system
Instead of doing wc -l /proc/net/tcp, is there a faster way of doing it?
I just need a total count of tcp connections.
0
votes
0answers
43 views
How to tune Unix (Ubuntu) for web crawling?
What are some ways to tune some Unix settings in the kernel(or elsewhere) for web crawling purposes? I am using multi-curl, and am using a multi-threading approach. I've set a higher limit for maximum ...
1
vote
1answer
370 views
Is there a faster interface for info from /proc/net/tcp?
Given a linux TCP socket's inode (obtained via /proc/<pid>/fd), is there a faster way to look up the information that I can get from /proc/net/tcp about this socket?
I have written a ...
1
vote
1answer
138 views
Default value for SO_RCVTIMEO option on Solaris
Is there any way to find out what is the default value set for option SO_RCVTIMEO on Solaris 10?
If there is a way to find out how would one go about changing it?
P.S. I am aware of ability of ...
1
vote
2answers
95 views
Port forwarding and masquerading
What is the relationship between port-forwarding and masquerading?
If server A is configured to masquerade its clients, and client B accesses the Internet through server A,
then since client B is ...
5
votes
2answers
105 views
Is it more dangerous to connect to the net as root?
If I make some kind of tcp connection to the net as root, is that less safe then making the same tcp connection as a normal user?
I have been suspecting for a while that by making a connection as ...
2
votes
1answer
176 views
Running a local port scan and found open ports but, don't know what they're used for?
I wrote a very basic python script to port scan my system. I'm running linux-mint lisa:
open_ports = []
for port in xrange(65536):
conn = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
...
3
votes
3answers
344 views
What process is sending TCP SYNs on Solaris 10?
Some process on my Solaris 10 machine is sending TCP SYNs to a remote machine. The remote machine never responds, so the connection is not established. How do I find out what process is initiating ...
3
votes
2answers
258 views
Meaning of log entries from an iptables configuration
My router has Linux as its OS. The system log has a lot of rows about iptable and klogd that I don't understand, could someone explain them to me?
The iptables setup:
iptables -t nat -A PREROUTING ...
4
votes
3answers
305 views
How can I know the process name which is opening a tcp port?
I have two linux servers. Let's say they are C and S.
C is client of S
On my S machine, I type.
$ netstat -an | grep ESTABLISHED
tcp 0 0 192.168.1.220:3306 C:57010 ...
3
votes
2answers
2k views
Fast way to copy a large file on a LAN
I am having some trouble with NFS, and I'd like to try using just plain old TCP.
I have no idea where to begin, though.
Hardware-wise, I am using an ethernet crossover cable to network two netbooks.
...
2
votes
1answer
139 views
How do I ensure outbound TCP/IP traffic always uses a VPN, even when using Wifi?
I'd like to ensure that my VPN is started and running, before any TCP traffic from any of my background services send or receive data. How can I guarantee that this is the case?
How do I handle ...
1
vote
1answer
541 views
Adjusting rsync TCP timeout
I'm using rsync in my own C++ program by issueing the command system("rsync -rauzvq root@host:/folder");
I use this for keeping multiple systems in sync.
Now I have the problem that when a remote ...
2
votes
1answer
175 views
Closing socket connection on running console application
I am testing a chat bot and want to gracefully handle for times when the chat server isn't running so it can come back up when the service is available again. I have the programming handled. My ...
2
votes
1answer
252 views
Memory ussage for TCP or named pipe message buffers?
I have a group of programs that I was stress testing today. I drastically shot up the input load to the program and it worked at first, but I had an apparent memory leak sucking up memory. The only ...
3
votes
0answers
101 views
Socksifying a qemu-kvm using tsocks
I'm trying to socksify a qemu-kvm using tsocks, but I have no success.
I don't know if qemu access directly the hardware, skipping the OS or something like that, but I wasn't able to do this feat.
...
2
votes
2answers
314 views
What is the relation between DISPLAY :1.0 and port 5901
When I start a new X server using vncserver I can connect it using port 5901. From, say, a terminal, I can also do a:
export DISPLAY=:1.0
xterm
(it's just an example)
And I get an xterm on the ...
3
votes
2answers
120 views
How to detect out-bound port from PID
I have several applications that run on random ports. How would I take the pid or the file location and find which port it is running on?
Example of desired output:
www-data/apache = 80
...
4
votes
4answers
4k views
testing services/open ports with telnet?
I often see that folks test ports this way:
//shell
telnet ip-address 80
telnet ip-address 25
AFAIK telnet was the old way of getting onto some remote box - right? or so I thought...
Why exactly ...
4
votes
1answer
2k views
iptables port-mirroring
I need to be able to get a copy of packets received on port 8001 to port 8002. I have tried the following but I get an error that --tee is undefined.
sudo iptables -t nat -A PREROUTING -p TCP -s ...
0
votes
1answer
510 views
Can't connect remotely to server running redhat (ec2)
I created a RedHat 6.1 VM with EC2. Logged in as root, I installed (unzipped) JDK1.7 in /root/bin/jdk1.7.0 and installed (unzipped) GlassFish 3.1.1 in /root/bin/glassfish3. I set JAVA_HOME and ...
3
votes
2answers
394 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 ...
