[ale] Why ALE hated my email and how I fixed it

Michael B. Trausch mbt at zest.trausch.us
Thu Nov 19 15:35:37 EST 2009


On Thu, 2009-11-19 at 15:09 -0500, Michael H. Warfield wrote:
> > bronosky.com.    IN    CNAME    bronosky.com.
> 
> Is that even valid?  No, it can't be.  For one thing, that would
> prohibit MX records or A records for that name.  You can't mix CNAME
> records with other resource types. 

I missed the recursion bit there, that would certainly be invalid
because it would resolve:

  LOOKUP bronosky.com -> RESULT CNAME bronosky.com

Which would result in an infinite loop if not detected; a CNAME, as I
recall (can't find the exact citation) can point to another CNAME but
shouldn't, instead it should point to a name that has an A (or AAAA)
record in DNS.  MX records can point to A or CNAME records, as long as
they're valid.

That said, I also thought it was bad practice to have second-level
domains resolve to a CNAME or A record at all, since it can cause
confusion with older mail systems (if example.org has an IP address,
older software wouldn't even bother looking up an MX record for it, for
example).

	--- Mike

-- 
Blog:  http://mike.trausch.us/blog/
Misc. Software:  http://mike.trausch.us/software/

“The greater danger for most of us lies not in setting our aim too
high and falling short; but in setting our aim too low, and achieving
our mark.” —Michelangelo



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