How Secondary DNS works
Secondary DNS configuration
How does Secondary DNS work?
Secondary DNS operates according to the following algorithm:
- DNS servers ns4-l2.nic.ru (or ns4-l3.nic.ru, ns4-l4.nic.ru, or ns4-l5.nic.ru depending on the domain level) send requests for zone retrieval to the primary DNS server, the IP address of which is specified in the service settings from the moment of its activation. If necessary, the IP address of the primary DNS server can always be changed.
- If receiving a zone from the primary DNS server is impossible at some point, the requests will be repeated periodically for 4 calendar days.
- If all DNS server requests are unsuccessful for 4 days, they are suspended for 4 calendar days.
- The DNS server ns8-l2.nic.ru (ns8-l3.nic.ru, ns8-l4.nic.ru or ns8-l5.nic.ru depending on the domain level) sends requests for zone retrieval to the primary DNS server specified in the service settings. If it is impossible to receive the zone from the primary server, then the requests are sent to the server ns4-l2.nic.ru (ns4-l3.nic.ru, ns4-l4.nic.ru or ns4-l5.nic.ru depending on the domain level).
Secondary DNS Setup
For Secondary DNS to function properly, you need:
- Specify the names of the provided DNS servers when delegating a domain.
- Configure primary and secondary DNS servers.
In the Secondary DNS settings, you need to specify the IP address of the primary DNS server from which the zone file for the domain should be obtained. You must specify the following DNS server names when delegating domains:
- second level
For domains such as domain.ru
| ns4-l2.nic.ru | 91.217.20.1 |
| ns8-l2.nic.ru | 91.217.21.1 |
| ns4-cloud.nic.ru | 185.42.137.111 2a01:3f0:400::62 |
| ns8-cloud.nic.ru | 194.58.196.62 2a01:3f1:862::53 |
- third level
For domains such as domain.msk.ru
| ns4-l3.nic.ru | 91.217.20.5 |
| ns8-l3.nic.ru | 91.217.21.5 |
- forth level
For domains such as sub.domain.spb.ru
| ns4-l4.nic.ru | 91.217.20.9 |
| ns8-l4.nic.ru | 91.217.21.9 |
- fifth level
For domains such as sub.sub.domain.spb.ru
| ns4-l5.nic.ru | 91.217.20.13 |
| ns8-l5.nic.ru | 91.217.21.13 |
Allow zone transfers for the following IP addresses:
| 91.217.20.0/26 |
| 91.217.21.0/26 |
| 194.226.96.192/28 |
| 31.177.66.192/28 |
To ensure timely updating of the domain zone on the Secondary DNS servers, it is necessary to configure the sending of notify on the primary DNS server. For second-level domains, configure notify on the addresses ns4-l2-n.nic.ru, ns8-l2-n.nic.ru. For 3-5-level domains, configure notify on the addresses of secondary DNS servers specified during delegation: ns4-l*.nic.ru, ns8-l*.nic.ru.
If the sending of notify is not configured on the primary DNS server, the changed domain zone on the servers ns4-l*.nic.ru, ns8-l*.nic.ru will be updated in accordance with the value of the Refresh parameter in the SOA record, but not less than in 1 hour.