wallet2: don't use DNS to obtain segregation heights

[tobtoht]

Related: #8407

There are no other places where DNS is used in wallet2, so the --no-dns flag can be removed.

[sethforprivacy]

Just confirming that the hard-coded DNS addresses here match what I'm seeing in packet captures when attempting to generate transactions with Cake Wallet (which uses wallet2). Thanks for the quick PR!

[selsta]

+1 for removing the segregation heights code. Maybe it would make sense to keep the --no-dns option for now. It might be needed in the future and also functionality can be added to disable OpenAlias when --no-dns is specified, which would be nice for privacy. Obviously this would be done in a separate patch. What do you think @tobtoht?

[tobtoht]

@selsta

Suggestion adopted in the interest of getting this patch merged before the v0.18 tag. We can discuss how wallets should handle OpenAlias in a separate issue.

[selsta]

Code reviewed and tested.

[jeffro256]

Beautiful. The fewer DNS requests made, the better everyone's privacy is

[jeffro256]

This feature was added in #3419 by @moneromooo-monero. @moneromooo-monero what are your thoughts about this PR?

[selsta]

@jeffro256 There are no TXT records added to e.g. segheights.moneropulse.org so I don't think this was ever used. Back in 2018 there was this MoneroV fork so that's why this got added, see for example:

https://monero.stackexchange.com/questions/7826/how-can-individuals-safeguard-themselves-and-the-community-against-a-key-reusing

If this is ever needed in the future and also if this is deemed as the right approach we can trivially revert it and bring it back in a point release.