Difference between revisions of "Networking"

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(Interfaces)
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[[Category:networking]]
 
[[Category:networking]]
 
[[Category:Linux/Unix]]
 
[[Category:Linux/Unix]]
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==Check network connections==
 
==Check network connections==
  
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:Now if you connect to port 8080 on your local server you are connected to port 3006 on the remotehost
 
:Now if you connect to port 8080 on your local server you are connected to port 3006 on the remotehost
 
:Using <code>-nNT</code> prevents that the ssh command opens a terminal on the proxy. The ssh command however must remain active.
 
:Using <code>-nNT</code> prevents that the ssh command opens a terminal on the proxy. The ssh command however must remain active.
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 +
==Tracing==
 +
For tracing traffic see [[Tcpdump]]

Revision as of 08:50, 27 November 2019


Check network connections

Netcat

nc -v -z <host> <port>
Tell me if we can open a connection to <host> on <port>. Without -z it works like telnet
nc -v -u -z <host> <port>
Tell me if we can open a connection to <host> on a UDP <port>

Curl

curl -vvv -k --proxy1.0 <proxyIP>:<proxyPort> <Remote URL>
Get the data from <remote URL> via <proxyIP> -k allows insecure SSL connections
curl -vvv telnet://<IP>:<port>
Just test connectivity to a port
#!/bin/bash

PORT=$1

TARGETS="999.999.999.999
888.888.888.888
777.777.777.777
666.666.666.666
"

for TARGET in ${TARGETS}
do
  curl  http://${TARGET}:${PORT} --connect-timeout 1 > /dev/null 2>&1
  if [ $? == 28 ]
   then
    echo No connection to ${TARGET}:${PORT}
  fi
done

Wget

wget <URL>
Get the data from <URL>

OpenSSL

See the OpenSSL page

Interfaces

ifconfig -a
Show all network interfaces
ifconfig <interface> <ipaddrss>
Assign <ipaddress> to <interface>
mii-tool <interface>
Show interface link status (speed)
The interfaces file
apt-get purge network-manager
vi /etc/network/interfaces
auto <interface>
iface <interface> inet dhcp
    wpa-ssid <ssid>
    wpa-psk <password>

For interfaces that may not be connected use allow-hotplug instead of auto.
The bootprocces now does not wait for an DCHP-answer on disconnected interfaces. Saves you about 5 minutes during startup.

Tunneling

ssh -L 8080:remotehost:3006 proxy
Login over ssh to proxy and there connect to remotehost port 3006. Connect local port 8080 to the remote connection.
Now if you connect to port 8080 on your local server you are connected to port 3006 on the remotehost
Using -nNT prevents that the ssh command opens a terminal on the proxy. The ssh command however must remain active.

Tracing

For tracing traffic see Tcpdump