packets per second.

Block IP options

Check the box to activate the Block IP options function. The Vigor

 

router will ignore any IP packets with IP option field in the

 

datagram header. The reason for limitation is IP option appears to

 

be a vulnerability of the security for the LAN because it will carry

 

significant information, such as security, TCC (closed user group)

 

parameters, a series of Internet addresses, routing messages...etc.

 

An eavesdropper outside might learn the details of your private

 

networks.

Block Land

Check the box to enforce the Vigor router to defense the Land

 

attacks. The Land attack combines the SYN attack technology with

 

IP spoofing. A Land attack occurs when an attacker sends spoofed

 

SYN packets with the identical source and destination addresses, as

 

well as the port number to victims.

Block Smurf

Check the box to activate the Block Smurf function. The Vigor

 

router will ignore any broadcasting ICMP echo request.

Block trace router

Check the box to enforce the Vigor router not to forward any trace

 

route packets.

Block SYN fragment

Check the box to activate the Block SYN fragment function. The

 

Vigor router will drop any packets having SYN flag and more

 

fragment bit set.

Block Fraggle Attack

Check the box to activate the Block fraggle Attack function. Any

 

broadcast UDP packets received from the Internet is blocked.

 

Activating the DoS/DDoS defense functionality might block some

 

legal packets. For example, when you activate the fraggle attack

 

defense, all broadcast UDP packets coming from the Internet are

 

blocked. Therefore, the RIP packets from the Internet might be

 

dropped.

Block TCP flag scan

Check the box to activate the Block TCP flag scan function. Any

 

TCP packet with anomaly flag setting is dropped. Those scanning

 

activities include no flag scan, FIN without ACK scan, SYN FINscan,

 

Xmas scan and full Xmas scan.

Block Tear Drop

Check the box to activate the Block Tear Drop function. Many

 

machines may crash when receiving ICMP datagrams (packets) that

 

exceed the maximum length. To avoid this type of attack, the Vigor

 

router is designed to be capable of discarding any fragmented ICMP

 

packets with a length greater than 1024 octets.

Block Ping of Death

Check the box to activate the Block Ping of Death function. This

 

attack involves the perpetrator sending overlapping packets to the

 

target hosts so that those target hosts will hang once they

 

re-construct the packets. The Vigor routers will block any packets

 

realizing this attacking activity.

Block ICMP Fragment Check the box to activate the Block ICMP fragment function. Any

 

ICMP packets with more fragment bit set are dropped.

Block Unknown

Check the box to activate the Block Unknown Protocol function.

Protocol

Individual IP packet has a protocol field in the datagram header to

 

indicate the protocol type running over the upper layer. However,

 

the protocol types greater than 100 are reserved and undefined at

 

this time. Therefore, the router should have ability to detect and

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VigorPro5500 Series User’s Guide

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Draytek 5500 Series Block IP options, Block Land, Block Smurf, Block trace router, Block SYN fragment, Block TCP flag scan