Ask HN: Wasn't e-mail deliverability affected today for domains hosted with dyn? | Hacker News Reader

Ask HN: Wasn't e-mail deliverability affected today for domains hosted with dyn?

2 pointsnodesocket1 comment

If you tried to send an e-mail to foo@twitter.com during the dyn outage, would the message be delivered? Perhaps delivered eventually (delayed).

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> Perhaps delivered eventually (delayed).

This is how email is designed. Mail servers will continue to try to deliver for quite some time before giving up.

The email transmission protocol was designed way back in the day of intermittent internet connections, so it has already backed into its design the concept of retry some number of times before giving up.

FWIW, twitter uses google as their email:

    twitter.com     mail exchanger = 30 ASPMX3.GOOGLEMAIL.com.
    twitter.com     mail exchanger = 20 alt2.aspmx.l.google.com.
    twitter.com     mail exchanger = 30 ASPMX2.GOOGLEMAIL.com.
    twitter.com     mail exchanger = 20 alt1.aspmx.l.google.com.
    twitter.com     mail exchanger = 10 aspmx.l.google.com.

So anyone who had twitter's MX records cached in their local DNS servers would never have noticed a problem from the dyn outage (as least not until the cache expired).

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