Tcp Level Settings - D-Link DFL-260E User Manual

13.2. TCP Level Settings

13.2. TCP Level Settings
TCP Option Sizes
Verifies the size of TCP options. This function acts in the same way as IPOptionSizes described
above.
Default: ValidateLogBad
TCP MSS Min
Determines the minimum permissible size of the TCP MSS. Packets containing maximum segment
sizes below this limit are handled according to the next setting.
Default: 100 bytes
TCP MSS on Low
Determines the action taken on packets whose TCP MSS option falls below the stipulated
TCPMSSMin value. Values that are too low could cause problems in poorly written TCP stacks.
Default: DropLog
TCP MSS Max
Determines the maximum permissible TCP MSS size. Packets containing maximum segment sizes
exceeding this limit are handled according to the next setting.
Default: 1460 bytes
TCP MSS VPN Max
As is the case with TCPMSSMax, this is the highest Maximum Segment Size allowed. However,
this setting only controls MSS in VPN connections. This way, NetDefendOS can reduce the
effective segment size used by TCP in all VPN connections. This reduces TCP fragmentation in the
VPN connection even if hosts do not know how to perform MTU discovery.
Default: 1400 bytes
TCP MSS On High
Determines the action taken on packets whose TCP MSS option exceeds the stipulated
TCPMSSMax value. Values that are too high could cause problems in poorly written TCP stacks or
give rise to large quantities of fragmented packets, which will adversely affect performance.
Default: Adjust
TCP MSS Log Level
Determines when to log regarding too high TCP MSS, if not logged by TCPMSSOnHigh.
Default: 7000 bytes
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Chapter 13. Advanced Settings