As with a lot of things in life, a lot of technology requires patience. Patience for slow internet connections, for development of new tools, for ISPs to implement IPv6 in their networks, and for caches.

I was recently deploying IPv6 at an ISP, and with that setting up reverse DNS with RIPE for the allocated prefix. At one point RIPE will test you DNS server configuration, to ensure that you have not messed anything up and will not be able to serve PTR records. This makes a whole lot of sense. What does not make sense is that the RIPE service testing these records, apparently has a conservative cache for new records. This made the implementation follow the scheme:

  • Add domain along SOA and NS records to DNS servers
  • Try to verify configuration with RIPE
  • Wonder why configuration is failing
  • Read documentation and check records
  • Try once more with RIPE but fail again
  • Go to lunch wondering what the problem is
  • Come back and read documentation again, again checking records
  • Try with RIPE again nearing frustration
  • Suddenly everything works…

I understand the validity of being conservative with DNS, but this RIPE service might be one of the things that being conservative does not apply to.

A similar story concerns sending mail to Google via IPv6.

Sending single mails was working perfectly, after adding AAAA and PTR records for a outgoing mailserver, but as soon as larger scale mail started flowing, every second email or so would be rejected. Every server at Google was different, and each would reply as it saw fit. Learning from the earlier encounter with RIPE caches, I went to lunch, came back for testing, and suddenly everything worked.

More than ever, it seems that good technology, even though many things are moving fast, requires time and care.

Written on April 8, 2018