tcpdump servaddr.sin_addr.s_addr=htonl()

This command is incomplete and does not make sense. It appears to be an attempt to use the tcpdump command to capture network traffic based on the source or destination IP address, but it is missing important information such as the interface to capture on and the protocol to filter on. The use of htonl() suggests that the command may be attempting to convert the IP address to network byte order, but it is not clear what IP address is being used or why it needs to be converted. More information is needed to provide a complete and accurate answer.