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Re: port blocking fun

 Kristian Erik Hermansen wrote: 
> Does Comcast allow incoming udp/53?  If so, you could have run your 
> own authoritative DNS server configured with both MX and SRV records. 
> You would have been able to do this for free...heh 

The first problem with that is that my registrar requires that for my domain: 
  - there must be at least 2 unique NS servers 
  - you must refer to them by FQDN, not raw IP address 
That second one is the real stickler, although now that I think about it I 
might be able to trick them using DynDNS's DHCP-hostname service (unless they 
have a reverse-lookup requirement on the NS entries as well, I can't remember). 

The wiki page you sent about the SRV records indicated that some mail servers 
started supporting alternate ports for MX records in 2004.  It sounds like 
something that the big mail carriers wouldn't really make a priority to 
support (unlike, say, SPF records, which are also relatively new but many use 
for spam detection). 

It might be fun to do an experiment and see how many mail servers support SRV 
records.  I know how to get sendmail to listen on multiple ports, so I'd just 
need a way to determine from the logs which port incoming mail came in on. 
Too bad my DNS provider doesn't support SRV records... 


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