Obviously? I think I've had this phone call myself a few times, although in my experience it was never from a statistician and they didn't give me as much data, but I'm pretty sure the story is mostly accurate.
> I think this is nonsense... why would an invalid or incomplete sendmail configuration default to three milliseconds?
This is a wonderful question, and perhaps much more interesting than anything else in the page, but first, let's reproduce the timing;
My desktop, a 2017 Xeon E7-8880 (144 cores of 2.3ghz; 1tb ram) with a load of 2.26 at this moment:
$ time sleep 0.001
real 0m0.004s
user 0m0.001s
sys 0m0.003s
$ time sleep 0.001
real 0m0,002s
user 0m0,000s
sys 0m0,001s
Now as to why this is? Well in order to understand that, you need to understand how connect() actually works, and how to create a timeout for connect(). Those skilled in the art know you've got a number of choices on how to do it, but they all involve multiple steps because connect() does not take a timeout as an argument. Here's one way (not too different than what sendmail does/did):
fcntl(f,F_SETFL,O_NONBLOCK);
if(-1==connect(f,...)&&errno==EWOULDBLOCK){
fd_set a;FD_ZERO(&a);FD_SET(f,&a);
if(!select(f+1,&a,&a,NULL,{.tv_sec=0,.tv_usec=0})) {
close(f);return error;
}
}
For others, the surprise might be that it's still 3msec over twenty years later, and I think that is a much more interesting subject to explore than whether the speed of light exists.