I want to check what program is using some ports. I have
Code:
netstat -a | grep localhost
tcp 0 0 localhost:58935 localhost:www ESTABLISHED
tcp6 355 0 localhost:www localhost:58935 ESTABLISHED
udp 0 0 localhost:53888 localhost:53888 ESTABLISHED
I try ps aux | grep 53888. What other command can I use?
Is there any way to verify if packets being trafficked over a certain port are valid for the service you want to use this port for?
One obvious example that probably clarifies my question:
When I open port 443 (outgoing or incoming) for https/ssl traffic, I don't want this port to be used for say openvpn traffic.
Thus: when someone wants to surf to a website with https, it should be ok but if someone wants to connect to his home openvpn server over that same port, it should be blocked.
I'm using Ubuntu 9.10. My internet connection is an ADSL which I have set up using "pppoeconf". The connection starts at boot up. I can also start it if needed by using "sudo pon dsl-provider" and can stop it by using "poff dsl-provider".Recently I noticed that when I start my computer, there is some program (or programs) which is connecting automatically to the internet and downloading and uploading a lot of data. The data transferred can exceed 200 mb or 300 mb in an hour. I don't know what is being uploaded or downloaded.I know for sure that no file sharing programs like bittorrent clients are started at bootup so it is strange that this much data to be downloaded and uploaded without me sharing files or downloading files explicitly. The update software also does not run by default as I have opted to start it manually.
Is there any application which shows the programs that are connected to any particular port and transmitting and receiving data?In Windows XP I use a program called "What's Running" which clearly lists the programs using the different ports in the local machine and the remote IP addresses that the program is connected to. It also shows which program is transmitting and receiving data at any point in time. Is there any similar program for Linux?My internet connection is a data limited package otherwise I probably would not have bothered.
I have a third party program (tightvnc) which I want to monitor and detect if it loses a connection with a client. I don't care if the client has the program open but isn't doing anything with it, I only want to know if the actual TCP connection is lost.
Since TCP takes forever to die on it's own I was thinking the best way to detect if a connection is lost is by bandwidth the bandwidth on the tcp port allocated to the VNC connection. Are there any tools built in to redhat (RHEL 5.2) which I could use to do this? Since I don't have full control of the operating system I would prefer to use built in tools rather then trying to get a new tool installed.
I want to do a simple port redirect, i.e. whatever comes trough whatever interface on port AAAA will get redirected to port BBBBI thought that iptables -t nat -I PREROUTING --source 0/0 --destination 0/0 -p tcp --dport AAAA -j REDIRECT --to-ports BBBBhowever it doesn't work, e.g. nc -v -w2 -z localhost AAAA gives:
nc: connect to localhost port AAAA (tcp) failed: Connection refused
while
nc -v -w2 -z localhost BBBB
[code]....
I am writing some application in C, which will access a serial port device (RS232). My application is working good. But if any other application is already opened the port, I couldn't able to identify that. In windows VB program, while accessing comport through mscomm control, i am receiving an error as "Port Already Opened". But in Linux environment, through C program how can i get that? I am accessing comport 1 as follows
fd = open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_SYNC);
We are trying to create a message forwarder program that receive a message on Port A and pass it on t Port B. Also receive a message from Port C and Pass it on to Port D as follows.
[Code]...
How do I check port 3306 to see if it is being used? I am unable to get MySQL to run with a LAMPP 1.7.3a installedon Ubuntu 9.10. The Apache server and ProFTPD start fine.
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PS: There will be no voltage input involve (although I can if that's required)
I'm planning to use this with Nagios to know if we are on the electric network or on our diesel power generator.
my server get hanged when ever their is loading problem. i wanna a program to get cpu load and also when load get high from a specified load value it should restart service. is their is any programm or how to write that programm..
View 12 Replies View RelatedI have set up a user to login remotely to our Red Hat 5 server via SSH. A rule in our department firewall enables this user to login from a single static ip address. The ssh port on our server is 22. I am able to login to port 22 from locations within our department firewall. Our administrator says the firewall configuration is unchanged. The remote user had been successful logging in. But now the remote user gets a Connection Timed Out message, before being asked to authenticate by the server.
I regenerated security keys, but the remote user still gets the connection timed out message. (I can login locally with the new keys). I suspect either a firewall or an authentication problem--inclining a firewall problem. Am I correct? Is there a Linux command to check whether port 22 is available or blocked, prior even to authentication, for login from the user's remote location?
I'm not talking about like:
apt-get check
I mean it's like, and I thought it was this:
valgrind <application>
Needs:
x
y
z
Does anyone know what I'm talking about? A lot of programs I'm getting segmentation faults like Rhythmbox, a few games, etc. so I dunno.
EDIT: gdb kind of works, but doesn't show me what another program would..
My internet connection is really bad,so I need some kind of program to make a text file or something saying when internet connection is gone and time and date,also if possible to say why is it gone,is it my problem or is it my internet providers problem.
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View 10 Replies View RelatedWhen I use the following command:
ssh user@ssh_server -L 5500:localhost:5500 -p 22
everything works fine. I can log in, and local port forwarding is done. Otherwise when I use the command:
ssh user@ssh_server -R 5500:localhost:5500 -p 22
I get an error "remote port forwarding failed for listen port 5500". However when I try remote port forwarding in WinXP by use of putty there is no problem...
I'm trying to use iptables in order to forward all the incoming packets for port 5555 to port 5556 on the same server (192.168.2.101).
I wrote the following commands:
iptables -A PREROUTING -t nat -i any -p tcp --dport 5555 -j DNAT --to 192.168.2.101:5556
iptables -A FORWARD -p tcp -m state --state NEW -d 192.168.2.101 --dport 5556 -j ACCEPT
How to check the version of a program, in particular geant4, in linux using the command lines?
View 4 Replies View RelatedI want to check whether a USB is plugged in its slot from a C program. I want to make use of /proc interface for the same. During my reading i found that /proc/bus/usb/devices will tell how many USB devices are currently present.
So whether i can open this file and use stat call to identify whether the size is 0. If size is 0, i can assume no USB present. Else i can assume USB is present.
Whether my understanding correct. If USB inserted, how can i check the folders present in the USB stick.
I'm using a Debian servers, as router/firwall.. I've two ethernet interfaces into the server, one for wan and one for lan. The i use SNAT so my LAN clients can access the internet throgh the debian router. That is working... Now i want to be able to access servers on the LAN site from the WAN site, and i wanna use port address translation (PAT). I have a FTP server running on a lan server, so i'm trying to portward port 21.
iptables -t nat -A PREROUTING -p tcp -i eth1 -d (WANIP) --dport 21 -j DNAT --to 192.168.1.2:21
When people try to access my FTP from the WAN site, they are redirected to the local FTP server, and they are promted for crendentials, but when the credentials are typed, and the local ftp server should answer the wan request, the connections dies.
The wan clients are being promted for credentials, so they are redirected to the local lan server, but after that the connections dies, so i think there is some kind of nat problem, when the local lan server is trying to respond to the wan request..
Here i my iptables script:
#flush table
iptables -F
#input regler
[code]....
I make an application on GNU/Linux which listening on a MULTICAST stream, so I open my unconnected socket, bind it on a MULTICAST address and a port, join the multicast group with the "setsockopt (IP_ADD_MEMBERSHIP)", then I receive datagram on my socket.
Now I've two different instances of the same application that run with their own MULTICAST address and port. And what I found strange is that, after a misconfiguration, I switch the ports, for example:
Emitting on 225.0.0.1/23451 and 225.0.0.2/23452
Receiving on 225.0.0.1/23452 and 225.0.0.2/23451
And my receiving part doesn't care about the MULTICAST address, it looks like the socket is listening on the port number only! I mean that the receiver [225.0.0.1/23452] take its datagrams from emitter [225.0.0.2/23452] and vice-versa!
Is there a program, or command, that will allow me to recursively check a web site for broken links?
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View 2 Replies View RelatedI had to add them to my firewall script when I installed openvpn on my dd-wrt router:
iptables -I FORWARD -i br0 -o tun0 -j ACCEPT
iptables -I FORWARD -i tun0 -o br0 -j ACCEPT
iptables -I INPUT -i tun0 -j REJECT
iptables -t nat -A POSTROUTING -o tun0 -j MASQUERADE
what should I add/change to set up port forwarding of port 1000 to ip 192.168.1.200. also how to get the answer sent by 192.168.1.200 follow the same route used by the data received through port forwarding.
I've killed apache via /etc/init.d/apache2 stop, but something is still listening on port 80:
Code:
root@www:/etc/apache2/sites-enabled# netstat -an | grep LISTEN | grep 80
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:8022 0.0.0.0:* LISTEN
unix 2 [ ACC ] STREAM LISTENING 5806 /var/run/mysqld/mysqld.sock
How do I find out that program this is?, or how to I stop it listening?