Category: tcp/ip

  • Problems (and a semi-solution) for tcpdump with DAG cards

    Documenting here for posterity, since I didn’t find much information about it on the ‘net: Disclaimer: I’m not a network head, just an amateur who dabbles with it when he needs to fix a problem. Given one Ninjabox (the nickname for packet capture boxes from Endace) with a DAG card (some kind of custom packet […]

  • How to save/restore iptables rules on Ubuntu?

    This might be an obvious thing to old Linux-heads out there, but it sure caught me off-guard, so there might be some use in spelling it out: iptables-save and iptables-restore do not actually save/load the iptables rules to/from an external file. You are responsible for redirecting the output of iptables-save to a file and modifying […]

  • What to do if you have many TIME_WAIT connections owned by the system process?

    If you have a Windows machine which acts as a server and it have many connections per seconds, you can get in the situation when you have a lot of half-open connections owned by the system (PID 0) process. To resolve this if the communication hosts have high speed connections with one another (like a […]