ZyXEL Communications 5 Series - Manual (Page 512)

ZyWALL 5/35/70 Series User’s Guide
512 Chapter 30 Logs Screens
Exceed maximum sessions per host
(%d).
The device blocked a session because the host's
connections exceeded the maximum sessions per host.
Firewall allowed a packet that
matched a NAT session: [ TCP |
UDP ]
A packet from the WAN (TCP or UDP) matched a cone
NAT session and the device forwarded it to the LAN.
Table 168 TCP Reset Logs
LOG MESSAGE DESCRIPTION
Under SYN flood attack,
sent TCP RST
The router sent a TCP reset packet when a host was under a SYN
flood attack (the TCP incomplete count is per destination host.)
Exceed TCP MAX
incomplete, sent TCP RST
The router sent a TCP reset packet when the number of TCP
incomplete connections exceeded the user configured threshold.
(the TCP incomplete count is per destination host.) Note: Refer to
TCP Maximum Incomplete in the Firewall Attack Alerts screen.
Peer TCP state out of
order, sent TCP RST
The router sent a TCP reset packet when a TCP connection state
was out of order.Note: The firewall refers to RFC793 Figure 6 to
check the TCP state.
Firewall session time
out, sent TCP RST
The router sent a TCP reset packet when a dynamic firewall
session timed out.
The default timeout values are as follows:
ICMP idle timeout: 3 minutes
UDP idle timeout: 3 minutes
TCP connection (three way handshaking) timeout: 270 seconds
TCP FIN-wait timeout: 2 MSL (Maximum Segment Lifetime set in
the TCP header).
TCP idle (established) timeout (s): 150 minutes
TCP reset timeout: 10 seconds
Exceed MAX incomplete,
sent TCP RST
The router sent a TCP reset packet when the number of
incomplete connections (TCP and UDP) exceeded the user-
configured threshold. (Incomplete count is for all TCP and UDP
connections through the firewall.)Note: When the number of
incomplete connections (TCP + UDP) > “Maximum Incomplete
High”, the router sends TCP RST packets for TCP connections
and destroys TOS (firewall dynamic sessions) until incomplete
connections < “Maximum Incomplete Low”.
Access block, sent TCP
RST
The router sends a TCP RST packet and generates this log if you
turn on the firewall TCP reset mechanism (via CI command: "sys
firewall tcprst").
Table 167 Access Control Logs (continued)
LOG MESSAGE DESCRIPTION