[...] > I'm running Exim 4.12 on Solaris 8. A misconfigured Exchange server is
> sending me a HELO name with an underscore in it. [...]
Can I just say thanks to the many people who responded, both on- and off-
list, with information and advice. As a result, I will be continuing
with the battle for a bit longer ...
Talking of battles, I'll just say that it was never my intention that this
query degenerate into a "debate" about reverse DNS, though given how often
that particular debate resurfaces on this list, I'm not surprised that it
did. I'm staying well out of it :-)