Default: 7000 bytes
TCP Auto Clamping
Automatically clamp TCP MSS according to MTU of involved interfaces, in addition to
TCPMSSMax.
Default: Enabled
TCP Zero Unused ACK
Determines whether NetDefendOS should set the ACK sequence number field in TCP packets to
zero if it is not used. Some operating systems reveal sequence number information this way, which
can make it easier for intruders wanting to hijack established connections.
Default: Enabled
TCP Zero Unused URG
Strips the URG pointers from all packets.
Default: Enabled
TCP Option WSOPT
Determines how NetDefendOS will handle window-scaling options. These are used to increase the
size of the window used by TCP; that is to say, the amount of information that can be sent before the
sender expects ACK. They are also used by OS Fingerprinting. WSOPT is a common occurrence in
modern networks.
Default: ValidateLogBad
TCP Option SACK
Determines how NetDefendOS will handle selective acknowledgement options. These options are
used to ACK individual packets instead of entire series, which can increase the performance of
connections experiencing extensive packet loss. They are also used by OS Fingerprinting. SACK is
a common occurrence in modern networks.
Default: ValidateLogBad
TCP Option TSOPT
Determines how NetDefendOS will handle time stamp options. As stipulated by the PAWS (Protect
Against Wrapped Sequence numbers) method, TSOPT is used to prevent the sequence numbers (a
32-bit figure) from "exceeding" their upper limit without the recipient being aware of it.
This is not normally a problem. Using TSOPT, some TCP stacks optimize their connection by
measuring the time it takes for a packet to travel to and from its destination. This information can
then be used to generate resends faster than is usually the case. It is also used by OS Fingerprinting.
TSOPT is a common occurrence in modern networks.
Default: ValidateLogBad
TCP Option ALTCHKREQ
13.2. TCP Level Settings
Chapter 13. Advanced Settings
557
Summary of Contents for NetDefend DFL-1660
Page 28: ...1 3 NetDefendOS State Engine Packet Flow Chapter 1 NetDefendOS Overview 28 ...
Page 88: ...2 6 3 Restore to Factory Defaults Chapter 2 Management and Maintenance 88 ...
Page 166: ...3 10 DNS Chapter 3 Fundamentals 166 ...
Page 254: ...4 7 5 Advanced Settings for Transparent Mode Chapter 4 Routing 254 ...
Page 268: ...5 4 IP Pools Chapter 5 DHCP Services 268 ...
Page 368: ...6 7 Blacklisting Hosts and Networks Chapter 6 Security Mechanisms 368 ...
Page 390: ...7 4 7 SAT and FwdFast Rules Chapter 7 Address Translation 390 ...
Page 414: ...8 3 Customizing Authentication HTML Pages Chapter 8 User Authentication 414 ...
Page 490: ...9 8 6 Specific Symptoms Chapter 9 VPN 490 ...
Page 528: ...10 4 6 Setting Up SLB_SAT Rules Chapter 10 Traffic Management 528 ...
Page 544: ...11 7 HA Advanced Settings Chapter 11 High Availability 544 ...
Page 551: ...12 3 5 Limitations Chapter 12 ZoneDefense 551 ...
Page 574: ...Default 512 13 9 Miscellaneous Settings Chapter 13 Advanced Settings 574 ...
Page 575: ...13 9 Miscellaneous Settings Chapter 13 Advanced Settings 575 ...