# DNS
###### tags: `IT`

## Powerdns
< 4.2.0
#### Powerdns API limitation :
一次傳輸大量的 records, powerdns 會回傳 status=500, text=Internal Server Error.

### 422 code removed
4.2 版之前可以用 422 去判斷 zone 是否已經存在．
但在 4.2 版之後 422 全部改成 404，所以會造成 octodns 出現 error 然後中斷．

https://github.com/PowerDNS/pdns/pull/6076

octodns patch
https://github.com/github/octodns/pull/540

## NS, zone 跟 CNAME 怎麼在 powerdns 裡面運作？
以下問題是很久以前問的，當時對 NS, ZONE...等還不熟
不過因為可以看得出來早期的認知所以留著
:::danger
什麼時候要設定 NS? 什麼時候要新增 ZONE? 什麼時候要設定 CNAME?
如果要訪問其他的 dns 要設定 NS 還是 CNAME (NS)
:::

## Cmds for dumpping DNS package
Dump 53 port to see DNS packages

sudo tcpdump -vv -i ens4 port 53

## dig
dig with a specific interface/IP

dig -b 192.168.2.7 github.com @8.8.8.8

## Must read
- [hello dns](https://powerdns.org/hello-dns/)

## reference
- [DNS Zones and Zone Files Explained](http://www.steves-internet-guide.com/dns-zones-explained/)
- [rfc 1034 - DOMAIN NAMES - CONCEPTS AND FACILITIES](https://datatracker.ietf.org/doc/html/rfc1034)
- [DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION](https://datatracker.ietf.org/doc/html/rfc1035)
- [RFC list related to DNS](https://powerdns.org/dns-camel/)
- [DNSSEC-bis for complete beginners](https://berthub.eu/dnssec/)
* [DNSSEC HOWTO - 2004](https://nsrc.org/workshops/2004/ccTLD-bkk/day3/dnssec_howto.pdf)
- [RFC-1035 DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION](https://www.ietf.org/rfc/rfc1035.txt)
- https://serverfault.com/questions/771744/how-can-i-determine-which-specific-process-service-on-my-centos-box-is-generatin
- https://www.reddit.com/r/linuxadmin/comments/ercx7l/ha_dns_solution/