Add second dns seeder

[aguycalled]

Adds a second dns seeder seed2.nav.community

; <<>> DiG 9.10.6 <<>> -t A seed2.nav.community
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 29564
;; flags: qr rd ra; QUERY: 1, ANSWER: 25, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;seed2.nav.community.		IN	A

;; ANSWER SECTION:
seed2.nav.community.	3598	IN	A	212.180.171.44
seed2.nav.community.	3598	IN	A	5.189.144.187
seed2.nav.community.	3598	IN	A	195.201.142.253
seed2.nav.community.	3598	IN	A	195.141.177.67
seed2.nav.community.	3598	IN	A	51.154.136.60
seed2.nav.community.	3598	IN	A	172.105.61.38
seed2.nav.community.	3598	IN	A	68.183.231.64
seed2.nav.community.	3598	IN	A	76.185.126.1
seed2.nav.community.	3598	IN	A	77.161.80.160
seed2.nav.community.	3598	IN	A	109.86.81.235
seed2.nav.community.	3598	IN	A	81.132.120.2
seed2.nav.community.	3598	IN	A	159.203.18.161
seed2.nav.community.	3598	IN	A	45.89.140.182
seed2.nav.community.	3598	IN	A	79.137.80.216
seed2.nav.community.	3598	IN	A	110.20.86.208
seed2.nav.community.	3598	IN	A	167.99.84.110
seed2.nav.community.	3598	IN	A	148.251.129.229
seed2.nav.community.	3598	IN	A	82.15.107.207
seed2.nav.community.	3598	IN	A	167.86.94.2
seed2.nav.community.	3598	IN	A	116.203.183.1
seed2.nav.community.	3598	IN	A	62.210.247.39
seed2.nav.community.	3598	IN	A	178.33.106.211
seed2.nav.community.	3598	IN	A	98.251.0.228
seed2.nav.community.	3598	IN	A	45.89.140.119
seed2.nav.community.	3598	IN	A	2.87.179.231

;; Query time: 34 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Mon Nov 18 12:53:33 CET 2019
;; MSG SIZE  rcvd: 448

What to test

Nodes should quickly find nodes without needing a previous list of known servers (this is achieved starting with a completely empty data folder).

[navbuilder]

A new build of 473f6dc has completed succesfully!
Binaries available at https://build.nav.community/binaries/dnsseed-redundancy

[mxaddict]

Tested with DIG command via CLI and DNS seed seems to be online at the time of writing, approving changes.

[mxaddict]

@aguycalled seems that seed.nav.community is not working, so only seed2.nav.community is working.

[aguycalled]

@mxaddict should be fixed now

$ dig -t a seed.nav.community


; <<>> DiG 9.10.6 <<>> -t a seed.nav.community
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 63486
;; flags: qr rd ra; QUERY: 1, ANSWER: 21, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;seed.nav.community.		IN	A

;; ANSWER SECTION:
seed.nav.community.	3599	IN	A	2.84.169.147
seed.nav.community.	3599	IN	A	73.202.231.123
seed.nav.community.	3599	IN	A	45.89.140.182
seed.nav.community.	3599	IN	A	159.203.18.161
seed.nav.community.	3599	IN	A	62.251.92.140
seed.nav.community.	3599	IN	A	2.87.179.231
seed.nav.community.	3599	IN	A	84.52.140.195
seed.nav.community.	3599	IN	A	159.203.28.37
seed.nav.community.	3599	IN	A	151.80.238.140
seed.nav.community.	3599	IN	A	87.189.124.25
seed.nav.community.	3599	IN	A	159.65.10.63
seed.nav.community.	3599	IN	A	159.69.187.24
seed.nav.community.	3599	IN	A	37.148.211.167
seed.nav.community.	3599	IN	A	212.180.171.44
seed.nav.community.	3599	IN	A	110.141.212.32
seed.nav.community.	3599	IN	A	178.33.106.211
seed.nav.community.	3599	IN	A	195.141.177.67
seed.nav.community.	3599	IN	A	195.201.142.253
seed.nav.community.	3599	IN	A	202.133.73.157
seed.nav.community.	3599	IN	A	172.105.61.38
seed.nav.community.	3599	IN	A	213.108.119.84

;; Query time: 70 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Tue Nov 19 23:39:01 CET 2019
;; MSG SIZE  rcvd: 383

[mxaddict]

I checked both seed.nav.community and seed2.nav.community, they are working.

@proletesseract @chasingkirkjufell can you guys review this PR?

[chasingkirkjufell]

Tested and worked as expected.