Thus, SYNs and application bytes (and FINs, which we will see later) are reliably delivered. ACKs, which do not consume sequence numbers, are not. 让我们直接来看真实的网络包吧~ Data Transmission 正常通信的过程,那就是对端的Ack=发送端的Seq+Len HTTP GET 请求 这是一次简单的HTTP GET 请求...
2. 在 16s 之后,TCP Stream 1 客户端 No.1044 SYN 发出,服务器响应了一个 ACK=158049099,乍看之下感觉 Num 158049099 出现的莫名其妙,但实际需要注意的是,Wireshark 默认的是 TCP 相对序列号,而不是绝对序列号。关闭 TCP Relative sequence numbers 选项后的信息如下 之前的相对序列号 158049099 ,实际上是绝对...
在TCP协议中,包含SYN标志的报文段(如SYN或SYN+ACK)会消耗一个序列号,即使不携带数据。SYN用于初始化序列号,其规则是每发送一个SYN,序列号递增1。ACK标志本身不消耗序列号。- **选项A(no)**:错误,SYN+ACK包含SYN,必须消耗一个序列号。 - **选项B(three)**:错误,没有机制会在此场景下消耗三个序列号。
containing a SYN bit and no ACK bit), and MAY send a TSopt in <SYN,ACK> only if it received a TSopt in the initial <SYN> segment for the connection. Once TSopt has been successfully negotiated, that is both <SYN> and <SYN,ACK> contain TSopt, the TSopt MUST be sent in every non...
However, if the destination server doesn't want to accept the packet for any reason, the server responds with an ACK+RST packet. In such cases, it's essential to investigate the application causing the reset (identified by port numbers) to understand why the connection is being re...
2 2.0786 BDC3 --> NTW3 TCP .A..S., len: 4, seq: 1109645-1109648, ack: 8221823, win: 8760, src: 139 (NBT Session) dst: 1037 BDC3 --> NTW3 IP TCP: .A..S., len: 4, seq: 1109645-1109648, ack: 8221823, win: 8760, src: 139 (NBT Session) dst: 1037 TCP: Source Port ...
TCP protocol -ACK packet retransmission in case we got FIN retransmission in TIME_WAIT state. Need to investigate this. TCP protocol -implement proper response to packets containing old SEQ and/or ACK numbers. Need to investigate this.
FIN-WAIT-1: When the sender has sent the FIN packet and is waiting for an ACK. FIN-WAIT-2: After receiving the ACK for the FIN packet. CLOSE-WAIT: When the receiver has received the FIN packet and acknowledged it. LAST-ACK: When the sender has received the FIN packet from the recei...
TCP: .A..., len:0, seq:925104-925104, ack:54857341, win:32722, src:1242 dst:139 TCP: Source Port = 0x04DA TCP: Destination Port = NETBIOS Session Service TCP: Sequence Number = 925104 (0xE1DB0) TCP: Acknowledgement Number = 54857341 (0x3450E7D) TCP: Data Offset = 44 (0x2...
_***_ _***_ Src Addr Dst Addr Protocol Description THEMACS1 NTBUILDS TCP ...S., len:0, seq:725163-725163, ack:0, win:65535, src:1217 dst:139 + FRAME: Base frame properties + ETHERNET: ETYPE = 0x0800 : Protocol = IP: DOD Internet Protocol + IP: ID = 0xB908; Proto = TCP...