b、ping进程1的fragment 1（分片的第二个报文）到锖螅�酚善骷觳榈礁帽ㄎ牡膇p Identifier的字段与fragment 0报文ip Identifier字段相同，因此路由器判断这两个报文是由同一个大的报文分片出来的，因此路由器将不在建立一个新的nat session表项，而是沿用第一个nat session表，然后将该报文转...
实际上windows系统就不在根据Identifier来区别ping进程了,它是根据Sequence Number field来区分的。
对于 ICMP 回显请求和应答报文来说,接下来是 16bits 标识符(Identifier)字段:用于标识本 ICMP 进程,区分不同的 PING 进程。对于 windows 系统来说,具体参考如下: Microsoft Windows NT - 256 Microsoft Windows 98/98SE - 512 Microsoft Windows 2000 – 512 最后是16bits序列号字段:用于判断回显应答数据报...
Checksum: This 16-bit field is used for error detection and ensures the integrity of the ICMP packet. Identifier: Used in ICMP echo request and reply messages to match requests with their corresponding replies. Sequence Number: This parameter, used in ICMP echo request and reply messages, helps...
(10.168.121.153) Version: 4 Header length: 20 bytes Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00: Not-ECT (Not ECN-Capable Transport)) 0000 00.. = Differentiated Services Codepoint: Default (0x00) ... ..00 = Explicit Congestion Notification: Not-ECT (Not ECN-Cap...
This ICMP packet still have Checksum、Identifier、Sequence number and data fields.Checksum field has 2 bytes. Sequence number fields has 2 bytes. Identifier field has 2 bytes. 4、Examine the corresponding ping reply packet. What are the ICMP type and code numbers? What other fields does this ...
Sequence number: The sequence number field in the Internet Control Message Protocol (ICMP) message is the sequence number for each host, and is incremented by 1 for each packet. The ID (identifier) and SEQUENCE (sequence number) are used to associate each echo request with its reply. ...
Identifier Sequence number Originate timestamp Receive timestamp Transmit timestamp Where: Type must be set to 14 Code must be set to 0 Identifier and Sequence number can be used by the client to match the reply with the request that caused the reply. Originate timestamp is the time ...
For computing the checksum , the checksum field should be zero. If the total length is odd, the received data is padded with one octet of zeros for computing the checksum. This checksum may be replaced in the future. Identifier If code = 0, an identifier to aid in matching echos and re...
这里我们假设Identifier字段为1， 写成00000000 00000001，假设Sequence Number字段为9，写成00000000 00001001...