Sandra G.
Dykes Sandra G.
Dykeshttpget [-r] [-l|-p|-v] [-t timeout] [-o outfile] [-h headerfile] URLtcping [-l|-p|-v] [-c count] [-i interval] [-t timeout] [-P port] host
To obtain httpget and tcping for UNIX, follow the usual download, gnuzip, and tar sequence: tar -xvf httpget.tar. Make and usage instructions are in the README.The httpget utility measures latency and bandwidth of Web object retrieval. It also prints Request and Response headers , and optionally saves the returned object. Httpget supports HTTP/1.1 headers, and can include additional arbitrary headers in the request. For example, you can attach a Cookie or entity tag to the request.
The tcping utility estimates network latency by measuring the round trip time for TCP header packets. The client sends a TCP SYN packet to an arbitrary (hopefully unused) port on the server. If the port is unused, the server responds with a TCP RST packet. The tcping utility is similar to standard ping programs in that it measures round trip time (RTT) to remote network locations. However, ping uses ICMP echo messages so under UNIX it must run as root or setuid, while tcping runs with user permissions. Consequently, tcping can be adapted into a user-level library function and called without the overhead of using system(). It can also be adapted to send concurrent SYN probes to multiple hosts without using threads or forks. Unfortunately, the SYN/RST technique does not allow packet size to be varied; packets are always TCP header packets without data. Because no TCP connection is establish, the SYN/RST probes avoid TCP window effects and do not result in TCP TIME_WAIT states. A word of warming: this utility resembles SYN attacks and may appear suspicious, although it is harmless when used as provided. It waits at least one second between SYNs, and requires fewer network and server resources than an actual Web download.
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