Monitoring Screen Counters
View screen statistics for a specified security zone.
Select Monitor>Security>Screen Counters in the J-Web user interface, or enter the following CLI command:
show security screen statistics zone zone-name
Table 47 summarizes key output fields in the screen counters display.
Table 47: Summary of Key Screen Counters Output Fields
Internet Control Message Protocol (ICMP) flood counter.
An ICMP flood typically occurs when ICMP echo requests use all resources in responding, such that valid network traffic can no longer be processed.
User Datagram Protocol (UDP) flood counter.
UDP flooding occurs when an attacker sends IP packets containing UDP datagrams with the purpose of slowing down the resources, such that valid connections can no longer be handled.
Number of Transport Control Protocol (TCP) WinNuke attacks.
WinNuke is a denial-of-service (DoS) attack targeting any computer on the Internet running Windows.
TCP Port Scan
Number of TCP port scans.
The purpose of this attack is to scan the available services in the hopes that at least one port will respond, thus identifying a service to target.
ICMP Address Sweep
Number of ICMP address sweeps.
An IP address sweep can occur with the intent of triggering responses from active hosts.
IP Tear Drop
Number of teardrop attacks.
Teardrop attacks exploit the reassembly of fragmented IP packets.
TCP SYN Attack
Number of TCP SYN attacks.
Number of IP spoofs.
IP spoofing occurs when an invalid source address is inserted in the packet header to make the packet appear to come from a trusted source.
ICMP Ping of Death
ICMP ping of death counter.
Ping of death occurs when IP packets are sent that exceed the maximum legal length (65,535 bytes).
IP Source Route
Number of IP source route attacks.
TCP Land Attack
Number of land attacks.
Land attacks occur when attacker sends spoofed SYN packets containing the IP address of the victim as both the destination and source IP address.
TCP SYN Fragment
Number of TCP SYN fragments.
TCP No Flag
Number of TCP headers without flags set.
A normal TCP segment header has at least one control flag set.
IP Unknown Protocol
Number of unknown Internet protocols.
IP Bad Options
Number of invalid options.
IP Record Route Option
Number of packets with the IP record route option enabled.
This option records the IP addresses of the network devices along the path that the IP packet travels.
IP Timestamp Option
Number of IP timestamp option attacks.
This option records the time (in Universal Time) when each network device receives the packet during its trip from the point of origin to its destination.
IP Security Option
Number of IP security option attacks.
IP Loose route Option
Number of IP loose route option attacks.
This option specifies a partial route list for a packet to take on its journey from source to destination.
IP Strict Source Route Option
Number of IP strict source route option attacks.
This option specifies the complete route list for a packet to take on its journey from source to destination.
IP Stream Option
Number of stream option attacks.
This option provides a way for the 16-bit SATNET stream identifier to be carried through networks that do not support streams.
Number of ICMP fragments.
Because ICMP packets contain very short messages, there is no legitimate reason for ICMP packets to be fragmented. If an ICMP packet is so large that it must be fragmented, something is amiss.
ICMP Large Packet
Number of large ICMP packets.
TCP SYN FIN Packet
Number of TCP SYN FIN packets.
TCP FIN without ACK
Number of TCP FIN flags without the acknowledge (ACK) flag.
TCP SYN-ACK-ACK Proxy
Number of TCP flags enabled with SYN-ACK-ACK.
To prevent flooding with SYN-ACK-ACK sessions, you can enable the SYN-ACK-ACK proxy protection screen option. After the number of connections from the same IP address reaches the SYN-ACK-ACK proxy threshold, Junos OS rejects further connection requests from that IP address.
IP Block Fragment
Number of IP block fragments.