gpg 2.1.15, *no* keyservers found for submit/recv, "DNS query returned an error or no records: No such domain (nxdomain)"

[lists at ssl-mail.com]

I've installed

	gpg2 --version
		gpg (GnuPG) 2.1.15
		libgcrypt 1.7.3
		Copyright (C) 2016 Free Software Foundation, Inc.
		License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>
		This is free software: you are free to change and redistribute it.
		There is NO WARRANTY, to the extent permitted by law.

		Home: /home/test/.gnupg
		Supported algorithms:
		Pubkey: RSA, ELG, DSA, ECDH, ECDSA, EDDSA
		Cipher: IDEA, 3DES, CAST5, BLOWFISH, AES, AES192, AES256, TWOFISH,
		        CAMELLIA128, CAMELLIA192, CAMELLIA256
		Hash: SHA1, RIPEMD160, SHA256, SHA384, SHA512, SHA224
		Compression: Uncompressed, ZIP, ZLIB, BZIP2

I can generate key pairs and rev certs OK.

But when I try to upload/retrieve from any keyserver, I get "ERR 167772346 No keyserver available <Dirmngr>".

Here's an attempt with keyserver == pool @ hkps://hkps.pool.sks-keyservers.net

	gpg -v --debug-all --recv-keys 0x673A03E4C1DB921F
		gpg: reading options from '/home/test/.gnupg/gpg.conf'
		gpg: enabled debug flags: packet mpi crypto filter iobuf memory cache memstat trust hashing cardio ipc clock lookup extprog
		gpg: DBG: [not enabled in the source] start
		gpg: DBG: chan_3 <- # Home: /home/test/.gnupg
		gpg: DBG: chan_3 <- # Config: /home/test/.gnupg/dirmngr.conf
		gpg: DBG: chan_3 <- OK Dirmngr 2.1.15 at your service
		gpg: DBG: connection to the dirmngr established
		gpg: DBG: chan_3 -> GETINFO version
		gpg: DBG: chan_3 <- D 2.1.15
		gpg: DBG: chan_3 <- OK
		gpg: DBG: chan_3 -> KEYSERVER --clear hkps://hkps.pool.sks-keyservers.net
		gpg: DBG: chan_3 <- OK
		gpg: DBG: chan_3 -> KS_GET -- 0x673A03E4C1DB921F
		gpg: DBG: chan_3 <- ERR 167772346 No keyserver available <Dirmngr>
		gpg: keyserver receive failed: No keyserver available
		gpg: DBG: chan_3 -> BYE
		gpg: DBG: [not enabled in the source] stop
		gpg: random usage: poolsize=600 mixed=0 polls=0/0 added=0/0
		              outmix=0 getlvl1=0/0 getlvl2=0/0
		gpg: secmem usage: 0/65536 bytes in 0 blocks


I've tried a bunch of different keyservers with always the same result.

I added logging to dirmgr.conf

+	log-file   /var/log/gnupg/dirmngr.log

On the failed attempt this is the log tail

	2016-10-09 08:27:02 dirmngr[32460.0] permanently loaded certificates: 0
	2016-10-09 08:27:02 dirmngr[32460.0]     runtime cached certificates: 0
	2016-10-09 08:27:03 dirmngr[32460.0] DNS query returned an error or no records: No such domain (nxdomain)
	2016-10-09 08:27:03 dirmngr[32460.0] DNS query failed: System error w/o errno
	2016-10-09 08:27:03 dirmngr[32460.0] resolving 'hkps.pool.sks-keyservers.net' failed: System error w/o errno
	2016-10-09 08:27:03 dirmngr[32460.0] DNS query failed: System error w/o errno
	2016-10-09 08:27:03 dirmngr[32460.0] resolving 'hkps.pool.sks-keyservers.net' failed: System error w/o errno
	2016-10-09 08:27:03 dirmngr[32460.0] can't connect to 'hkps.pool.sks-keyservers.net': host not found
	2016-10-09 08:27:03 dirmngr[32460.0] error connecting to 'https://hkps.pool.sks-keyservers.net:443': Unknown host
	2016-10-09 08:27:03 dirmngr[32460.0] marking host 'hkps.pool.sks-keyservers.net' as dead
	2016-10-09 08:27:03 dirmngr[32460.0] host 'hkps.pool.sks-keyservers.net' marked as dead
	2016-10-09 08:27:03 dirmngr[32460.0] command 'KS_GET' failed: No keyserver available

This

	DNS query returned an error or no records: No such domain (nxdomain)

looks like a (R)DNS lookup problem from WITHIN dirmngr/gnupg

Here, from cmd line

	host hkps.pool.sks-keyservers.net
		hkps.pool.sks-keyservers.net has address 92.43.111.21
		hkps.pool.sks-keyservers.net has address 209.135.211.141
		hkps.pool.sks-keyservers.net has address 104.236.209.43
		hkps.pool.sks-keyservers.net has address 178.62.203.205
		hkps.pool.sks-keyservers.net has address 212.12.48.27
		hkps.pool.sks-keyservers.net has address 18.9.60.141
		hkps.pool.sks-keyservers.net has address 193.164.133.100
		hkps.pool.sks-keyservers.net has address 140.211.169.202
		hkps.pool.sks-keyservers.net has address 37.97.129.189
		hkps.pool.sks-keyservers.net has address 94.142.242.225
		hkps.pool.sks-keyservers.net has IPv6 address 2a03:b0c0:2:d0::6e3:a001
		hkps.pool.sks-keyservers.net has IPv6 address 2606:9500:201:1::141
		hkps.pool.sks-keyservers.net has IPv6 address 2a02:898:31:0:48:4558:73:6b73
		hkps.pool.sks-keyservers.net has IPv6 address 2a01:7c8:aabc:45a:5054:ff:fe9b:59a3
		hkps.pool.sks-keyservers.net has IPv6 address 2604:a880:800:10::163:b001
		hkps.pool.sks-keyservers.net has IPv6 address 2a02:c205:3001:3626::1
		hkps.pool.sks-keyservers.net has IPv6 address 2a00:14b0:4200:3000:27::27
		hkps.pool.sks-keyservers.net has IPv6 address 2a01:4a0:59:1000:223:9eff:fe00:100f

	dig A hkps.pool.sks-keyservers.net
		; <<>> DiG 9.10.3-P4 <<>> A hkps.pool.sks-keyservers.net
		;; global options: +cmd
		;; Got answer:
		;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 18016
		;; flags: qr rd ra ad; QUERY: 1, ANSWER: 10, AUTHORITY: 0, ADDITIONAL: 1

		;; OPT PSEUDOSECTION:
		; EDNS: version: 0, flags:; udp: 4096
		;; QUESTION SECTION:
		;hkps.pool.sks-keyservers.net.  IN      A

		;; ANSWER SECTION:
		hkps.pool.sks-keyservers.net. 12 IN     A       92.43.111.21
		hkps.pool.sks-keyservers.net. 12 IN     A       18.9.60.141
		hkps.pool.sks-keyservers.net. 12 IN     A       178.62.203.205
		hkps.pool.sks-keyservers.net. 12 IN     A       104.236.209.43
		hkps.pool.sks-keyservers.net. 12 IN     A       209.135.211.141
		hkps.pool.sks-keyservers.net. 12 IN     A       37.97.129.189
		hkps.pool.sks-keyservers.net. 12 IN     A       212.12.48.27
		hkps.pool.sks-keyservers.net. 12 IN     A       140.211.169.202
		hkps.pool.sks-keyservers.net. 12 IN     A       193.164.133.100
		hkps.pool.sks-keyservers.net. 12 IN     A       94.142.242.225

		;; Query time: 0 msec
		;; SERVER: 10.19.2.100#53(10.19.2.100)
		;; WHEN: Sun Oct 09 08:28:06 PDT 2016
		;; MSG SIZE  rcvd: 217