On Thu, 02 Nov 2000 22:31:47 PST, Francois Gouget writes: > IIRC, most ping implementations send an 8 byte timestamp obtained >with gettimeofday as the payload of their ICMP echo request packets. >This payload is copied in the ICMP echo reply packets. So wwhen ping >receives an ICMP echo reply message that is addressed to itself >(matching icmp id), it just does another call to gettimeofday, substract >the timestamp that was returned, and print the RTT. > This way ping does not need to keep track of all the packets it sent >and thus does not need a timeout. It can even handle packets that come >back out of order.
yep, but most ping implementations ignore packets coming in after a given time, most of the time you need to do a ping -v to see them (requires root privileges on some machines because it wants to put the interface in promiscous mode where applicable). hth, &rw -- / Ing. Robert Waldner | Network Engineer | T: +43 1 89933 F: x533 \ \ <[EMAIL PROTECTED]> | KPNQwest/AT | Diefenbachg. 35, A-1150 /
