mailing list archives
Re: UDP port scanning...
From: Rob Quinn <rquinn () sec sprint net>
Date: Fri, 11 Feb 2000 07:29:35 -0500
- Kernel receives packet.
- Kernel checks to see if packet is a SYN, if so it allows other
existing items (such as ipfw, ipchains, tcp wrappers etc) to deal with it.
- If not a SYN, it checks to see if it is a part of an existing
conversation, and if it is, allows the packet (the state table).
- If not a part of an existing conversation, drop the packet (and
alternately log it).
What happens to a remote sender if your machine reboots during a TCP sessions?
131 ECONNRESET Connection reset by peer
A connection was forcibly closed by a peer. This
normally results from a loss of the connection on the
remote host due to a timeout or a reboot.
I don't understand why the above four steps are not standard in all networked
This could be suitable for a bastion host or firewall, but not a "standard
networked system". If some server of mine reboots or crashes, I want the
clients to know quickly so that they can start the recovery process ASAP,
instead of going through the TCP/IP timeout period.
| Opinions are _mine_, facts Rob Quinn |
| are facts. (703)689-6582 |
| rquinn () sec sprint net |
| Sprint Corporate Security |