Code Value

Data Length (bytes)

Name and Description

34

1

Trailer Encapsulation: When set to 1, tells the client to negotiate the use of trailers, as defined in RFC 893. A value of 0 tells the client not to use this feature.

35

4

ARP Cache Timeout: Specifies how long, in seconds, the client should hold entries in its ARP cache.

36

1

Ethernet Encapsulation: Tells the client what type of encapsulation to use when transmitting over Ethernet at layer two. If the option value is 0, specifies that Ethernet II encapsulation should be used, per RFC 894; when the value is 1, tells the client to use IEEE 802.3 encapsulation, per RFC 1042.

Code Value

Data Length (bytes)

Name and Description

37

1

Default TTL: Specifies the default Time To Live the client should use when sending TCP segments.

38

4

TCP Keepalive Interval: Specifies how long (in seconds) the client should wait on an idle TCP connection before sending a “keepalive” message. A value of 0 instructs the client not to send such messages unless specifically instructed to do so by an application.

39

1

TCP Keepalive Garbage: When set to 1, tells a client it should send TCP keepalive messages that include an octet of “garbage” for compatibility with implementations that require this.