[dns-operations] creeping poorness of judgement

Paul Vixie paul at redbarn.org
Sun Mar 15 01:49:11 UTC 2020


this part of my reply was mangled, so, retrying.

> > > here's what i'm going with, by the way:
> > > 
> > > _spf                    TXT     ( 	v=spf1\032
> > > 			2001:4f8::/32\032
> > > 			2001:559:8000::/48\032
> > > 			149.20.56.0/24\032
> > > 			24.104.150.0/24\032
> > > 			~all )
> > 
> > Well, you'd be much better off with the more readable, and
> > 
> > equally maintainable:
> >     @ TXT ( "v=spf1"
> >             " ip6:2001:4f8::/32"
> >             " ip6:2001:559:8000::/48"
> >             " ip4:149.20.56.0/24"
> >             " ip4:24.104.150.0/24"
> >             " ~all" )

thanks for the reminder about ip4: and ip6:, i've fixed that.

however, i won't encode spaces inside quoted strings, since they could accidently be tabs 
that render as single-column spaces. if a space is what the spec calls for, it's going to be 
an \040 in C, or a \032 in DNS.

also note, the _spf label is because i "include" these from apex TXT/SPF records, not 
because i believe that _spf is what the remote mail servers are going to be looking up. 
sorry for the confusion.

> [util.redbarn:amd64] dig +short redbarn.org txt | grep v=spf1 | cat -n
> 1  "v=spf1 " "include:_spf.tisf.net"
> [util.redbarn:amd64] dig +short _spf.tisf.net txt | grep v=spf1 | cat -n
> 1  "v=spf1 " "ip6:2001:4f8::/32 " "ip6:2001:559:8000::/48 "
> "ip4:149.20.56.0/24 " "ip4:24.104.150.0/24 " "~all"

-- 
Paul
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