Partial or empty TXT answers

[Miniwoffer]

First off great lib, okay so when I do resolver.ResolveCtx(ctx, "google.com.", "TXT") I get 6 TXT records:

Resolver settings:

var resolver *dnsr.Resolver = dnsr.NewResolver(dnsr.WithTimeout(5*time.Second), dnsr.WithCache(10000), dnsr.WithExpiry())

==================== Test output for //ogcode/services/certificate-bot/lib/resolver:resolver_test:
╭─── resolve("google.com.", "TXT", 1)
│   ╭─── resolve("google.com.", "NS", 2)
│   │   ╭─── resolve("com.", "NS", 3)
    X    29ms (T- 4999ms): dig +norecurse @b.root-servers.net. com. NS  # rmsg: NOERROR Answer: 0 NS: 13 Extra: 12 == CANCELED ==
X    26ms (T- 4990ms): dig +norecurse @a.gtld-servers.net. one.com. NS  # rmsg: NOERROR Answer: 0 NS: 2 Extra: 0 == CANCELED ==
│   │   │    9ms (T- 4999ms): dig +norecurse @e.root-servers.net. com. NS  # rmsg: NOERROR Answer: 0 NS: 13 Extra: 15
│   │   ╰─── 9ms: resolve("com.", "NS", 3) # [26]RR = NS(com.)=a.gtld-servers.net. NS(com.)=b.gtld-servers.net. ...
│   │    7ms (T- 4990ms): dig +norecurse @b.gtld-servers.net. google.com. NS  # rmsg: NOERROR Answer: 0 NS: 4 Extra: 8
│   ╰─── 17ms: resolve("google.com.", "NS", 2) # [8]RR = NS(google.com.)=ns2.google.com. NS(google.com.)=ns1.google.com. ...
        X    29ms (T- 4999ms): dig +norecurse @b.root-servers.net. com. NS  # rmsg: NOERROR Answer: 0 NS: 13 Extra: 12 == CANCELED ==
    X    26ms (T- 4990ms): dig +norecurse @a.gtld-servers.net. google.com. NS  # rmsg: NOERROR Answer: 0 NS: 4 Extra: 8 == CANCELED ==
│    36ms (T- 4982ms): dig +norecurse @ns1.google.com. google.com. TXT  # rmsg: NOERROR Answer: 6 NS: 0 Extra: 0
╰─── 54ms: resolve("google.com.", "TXT", 1) # [10]RR = TXT(google.com.)=google-site-verification=wD8N7i1JTNTkezJ49swvWW48f8_9xveREV4oB-0Hf5o TXT(google.com.)=MS=E4A68B9AB2BB9670BCE15412F62916164C0B20BB ...
TXT google-site-verification=wD8N7i1JTNTkezJ49swvWW48f8_9xveREV4oB-0Hf5o
TXT MS=E4A68B9AB2BB9670BCE15412F62916164C0B20BB
TXT facebook-domain-verification=22rm551cu4k0ab0bxsw536tlds4h95
TXT globalsign-smime-dv=CDYX+XFHUw2wml6/Gb8+59BsH31KzUr6c1l2BPvqKX8=
TXT docusign=1b0a6754-49b1-4db5-8540-d2c12664b289
TXT apple-domain-verification=30afIBcvSuDV2PLX
NS ns2.google.com.
NS ns1.google.com.
NS ns3.google.com.
NS ns4.google.com.

but if i try dig i get a lot more TXT records

> dig +norecurse +short @ns2.google.com. google.com. TXT
"docusign=05958488-4752-4ef2-95eb-aa7ba8a3bd0e"
"docusign=1b0a6754-49b1-4db5-8540-d2c12664b289"
"globalsign-smime-dv=CDYX+XFHUw2wml6/Gb8+59BsH31KzUr6c1l2BPvqKX8="
"MS=E4A68B9AB2BB9670BCE15412F62916164C0B20BB"
"webexdomainverification.8YX6G=6e6922db-e3e6-4a36-904e-a805c28087fa"
"facebook-domain-verification=22rm551cu4k0ab0bxsw536tlds4h95"
"google-site-verification=wD8N7i1JTNTkezJ49swvWW48f8_9xveREV4oB-0Hf5o"
"atlassian-domain-verification=5YjTmWmjI92ewqkx2oXmBaD60Td9zWon9r6eakvHX6B77zzkFQto8PQ9QsKnbf4I"
"v=spf1 include:_spf.google.com ~all"
"apple-domain-verification=30afIBcvSuDV2PLX"
"google-site-verification=TV9-DBe4R80X4v0M4U_bd_J9cpOJM0nikft0jAgjmsQ"
"onetrust-domain-verification=de01ed21f2fa4d8781cbc3ffb89cf4ef"

I also tried with cloudflare.com. it should have a bunch of TXT records but dnsr returns 0 TXT records.

[Miniwoffer]

I wrote some tests: https://github.com/domainr/dnsr/pull/112

[Miniwoffer]

I found out that changing from TCP to UDP in exchangeIP seems to fix the issue

[Miniwoffer]

Looks like tc bit is set on the response, so it should discard and retry on TCP.

[Miniwoffer]

Il write a fix