In the HTTP header, which of the following header fields indicates the domain name of the server (for virtual hosting) and the TCP port number on which the server is listening?
- urgent pointer
The host field indicates the domain name of the server (for virtual hosting) and the TCP port number on which the server is listening.
Other examples of HHTP header fields are:
– Accept – Media type(s) that is (/are) acceptable for the response
– Content-Length – The length of the request body in octets (8-bit bytes)
– From – The email address of the user making the request
– Referrer – the address of the previous web page from which a link to the currently requested page was followed
– Host – The domain name of the server (for virtual hosting), and the TCP port number on which the server is listening
– Date – The date and time that the message was originated
– Authorization – Authorization credentials for HTTP authentication
There is no urgent pointer field in an HTTP header. This field is found in TCP headers. The following lists the fields found in a TCP header:
– Urgent Pointer: Refers to the first urgent data byte in the packet.
– Sequence Number: Refers to the first byte of data in the current message. This field helps TCP to reassemble the packets in the correct order. For example, when data is transferred between an FTP server and FTP client, the receiver uses this field to reassemble the packets into the original file.
– Data Offset: Refers to the number of 32-bit words in the TCP header.
– Windows: Refers to the size of the available space for the incoming data.
– Source Port and Destination Port: Refer to the point where upper-layer source and destination processes receive TCP services. Both TCP and UDP packets contain these fields.
– Acknowledgement Number: Refers to the sequence number of the next byte of data that the sender will receive.
– Reserved: Reserved for future use.
– Flags: Contains control information, such as the SYN and ACK bits which are used to establish and acknowledge communication, and the FIN bit which is used to terminate the connection.
– Checksum: An indicator of any damage to the header while being in transit. Both TCP and UDP packets contain this field.
– Options: Used to specify TCP options. Only TCP packets this field.
– Data: has upper-layer information.