Comment 5 for bug 84104

Micah Cowan wrote:
> There is no software anywhere that would ever do a DNS lookup before
> each packet in a TCP connection. For one thing, that would be just
> ridiculously expensive, at least doubling the number of packets being
> sent out, and imposing huge delays as the application waits for the DNS
> response. For another, once a TCP connection is established, all packets
> must necessarily be between the same IP addresses. A "connection" is
> defined by an address/port pair on each end. If you change any of those,
> it's not the same connection anymore. Thirdly, once a connection has
> been established, the system kernel typically handles all the low-level
> packet sending, not the application. So, it really wouldn't make sense
> to have an option that controls DNS querying between packets for a
> single connection.
>
> As Diego indicated, wget caches DNS values by default, to enhance
> efficiency. If this is not the behavior you desire, you should use the
> --no-dns-cache option.
>
> ...However, I think your point that wget ought "to do everything it can"
> to succeed in reestablishing connection is a valid one. In the situation
> you've described, it's not possible for wget to avoid losing the initial
> connection, but if it fails in its second attempt, it should possibly
> attempt a DNS lookup. I'll go ahead and confirm this bug (I'm actually
> the upstream maintainer… as of yesterday!). I'll set the priority low,
> though, as there is a simple workaround (--no-dns-cache), and I have
> other things that will keep me busy for a while. :)
>
> ** Changed in: wget (Ubuntu)
> Importance: Undecided => Low
> Assignee: (unassigned) => Micah Cowan
> Status: New => Triaged
>
Thanks for listening.