Network Issues and how to troubleshoot them

Network Issue and how to Solve them


Tcp Dump

Is a very powerfull tool when looking into network related issues.


# Check If a port is sending data or receiving data
tcpdump -vvv port 10005

# Check if you are receiving anything from a ipaddress
tcpdump -n host

# Check if you are reciving anything from a port at an ipadress
tcpdump -vvv -n port 10006

# Specify if its a Source or Destination
tcpdump -vvv -n host and src port 3456
tcpdump -vvv -n src host and port 10006


Get the actual packet Content

# Get the packet content with tcpdump
tcpdump -nnvvXSs 1514



# Use netcat like this
nc -s -p 21


# Save the packets to a file
tcpdump -vvv -i eth0 host -s0 -w /tmp/hello.cap

# Show the packet header with the HEX
tcpdump -vvv -i eth0 host -s0 -X

# Show the raw packet directly in the console
tcpdump -vvv -i eth0 host -s0 -A



Posted on: Wednesday 13 January 2016