Your domain and/or changes to it are visible on SoftLayer's DNS servers immediately after the transfer completes. Due to the caching nature of DNS, there will be a delay before changes are visible on other DNS servers.
A secondary domain is a domain which SoftLayer's DNS servers transfer from your server to our Authoritative DNS servers, ns1.softlayer.comand ns2.softlayer.com. You can configure a secondary in the portal by clicking on Domain Name System in the Public Network folder in the Portal, clicking on the Secondary DNS link, and finally, clicking on Add Secondary DNS Record.
To setup a secondary domain, you'll need three pieces of information, the domain, the IP address of the master DNS server we're transferring from and how often, in minutes, you'd like the domain transferred.
Once a secondary domain is configured, you'll have the ability to change the master server's IP address and the transfer interval. You will also be able to view the domain as we're transferring, request a manual transfer, convert your secondary domain to a primary domain and view any error messages we logged during the transfer process.
1. What SoftLayer DNS servers will answer for my secondary domains?
SoftLayer's Anycast, IPv6 enabled Authoritative DNS Servers:
2. Where will the zone transfers come from?
Transfers of your secondary domain's will come any one of four IP addresses:
3. How long, after transferring a domain, does it take for that domain or changes to it to become visible?
The domain and/or changes to it will be visible on SoftLayer's DNS servers immediately after the transfer completes. Due to the caching nature of DNS, however, it may take a while for those changes to be visible on other DNS servers.
4. Are zone update notifies supported?
Notifies are not supported at this time.
5. How immediate is the Transfer Now button?
After clicking the transfer now button, the domain will be transferred a the beginning of the next minute.
6. Can a master be configured on the private network or will this have to go through the public?
Not at this time. All AXFR requests will be over the public network.
7. Will we remove slaves after a number of days in which the master is unavailable?
We will stop attempting to transfer a domain if it's master is down or misconfigured for a prolonged period. The portal provides customer feedback (the Error Messages tab) and a method of reactivating a domain (the Manual Zone Transfer tab) in the event there's issues transferring the zone and it is disabled as a consequence.
8. Is 1 minute the lowest transfer frequency?
9. If set to 1920 minutes then back to 10 will the 1920 minutes have to expire first before the new frequency goes into effect?
No. The system calculates the retransfer queue by taking the time of our last transfer ''attempt'' and adding the frequency to it. So, if you have frequency set to 1920 and you then change it to 10 minutes, as long as it's been at least 10 minutes since we last tried to transfer, we will retry immediately and then every 10 minutes thereafter.
The easiest way to run and manage your own nameservers is to use a control panel like Plesk or cPanel. Both have built in domain name servers that allow you to easily add/modify/delete domain names.
All you need to do is register your domain name as a nameserver with your domain name registrar and assign two IP addresses from your server(s) IP ranges.
We have two addresses for Authoritative Name Servers and two addresses for Resolving Name Servers.
Authoritative Name Servers
- ns1.softlayer.com 220.127.116.11
- ns2.softlayer.com 18.104.22.168
Resolving Name Servers
- rs1.service.softlayer.com 10.0.80.11
- rs2.service.softlayer.com 10.0.80.12
Public name servers act as authoritative name servers for domain names that reside in our DNS servers and are managed through the Customer Portal. These servers "answer" and "resolve" domain names to your IP address for the general internet population.
Resolving name servers are located on the private network and act as DNS resolvers for your server. The private resolvers query the Internet's root nameservers for domain lookups. For example, sending mail from your server requires an NSlookup of the destination domain name. The private DNS servers resolve this information over the private network to keep your bandwidth usage down, reduce the load on the authoritative servers, and offer quick resolution. Private network resolvers are a convenience service for our customers.
With a Bare Metal Server there are four typical options for name servers:
1. Use your domain name registrar name servers to manage your domain names
2. Use SoftLayer name servers to manage your domain names
3. Use a third party DNS service to manage your domain names
4. Run your own name servers on your server to manage your domain names
Numbers 1, 2, &3 will want use name
servers of the third party (ex. ns1.softlayer.com and ns2.softlayer.com).
Option number 4 will use your domain as the name server (ns1.yourdomain.com
& ns2.yourdomain.com). Option number 4 requires you to run DNS services on
your server and you must also register your domain as a name server with your
registrar. This is usually free, but requires an additional step beyond the
basic domain name registration process.
SoftLayer offers free DNS services that are fully managed through the customer portal. We highly recommend allowing SoftLayer to manage your DNS and to act as your name servers due to our redundant systems, ease of management, and ability to quickly troubleshoot DNS related issues.
SoftLayer does not require reverse DNS, but it is required by some Internet protocols and protocol extensions. Without reverse DNS, you may experience trouble with r-commands, IRC, some SMTP servers, most enterprise management systems, and many network backup systems. By using reverse DNS, you can ensure the smoothest experience possible.
DNS change propagation times depend on the time-to-live (TTL) setting for the DNS record.
The default TTL is one day, which means any modifications to a domain name take one day to propagate throughout the entire internet. TTL can be lowered if you plan to make changes frequently, however, the lower the TTL is, the higher the load becomes on the name server. Higher loads have a potential to increase the response time to end users, which could impact their overall satisfaction.
The higher the TTL setting, the higher DNS performance will be due to local ISP caching. The lower the TTL setting, the lower DNS performance will be due to increased name resolution.
To verify TTL, check the Start of Authority (SOA) record for the domain. A great tool for reviewing domain information is offered by CentralOps.net
TTL is listed in seconds.Divide by 60 to convert TTL to minutes, or by 3600 to convert to hours.
These are DNS resolvers located on the private network for your convenience. They provide fast ns-lookups for your server without utilizing your public bandwidth allotment.
The nameservers your servers use are:
Caching and time to live
Because of the huge volume of requests generated by a system like the DNS, the designers wished to provide a mechanism to reduce the load on individual DNS servers. The mechanism devised provided that when a DNS resolver (i.e. client) received a DNS response, it would cache that response for a given period of time. A value (set by the administrator of the DNS server handing out the response) called the time to live, or TTL defines that period of time. Once a response goes into cache, the resolver will consult its cached (stored) answer; only when the TTL expires (or when an administrator manually flushes the response from the resolver's memory) will the resolver contact the DNS server for the same information.
Generally, the time to live is specified in the Start of Authority (SOA) record. SOA parameters are:
Serial — the zone serial number, incremented when the zone file is modified, so the slave and secondary name servers know when the zone has been changed and should be reloaded.
Refresh — This is the number of seconds between update requests from secondary and slave name servers.
Retry — This is the number of seconds the secondary or slave will wait before retrying when the last attempt has failed.
Expire — This is the number of seconds a master or slave will wait before considering the data stale if it cannot reach the primary name server.
Minimum — Previously used to determine the minimum TTL, this is used for negative caching. This is the default TTL if the domain does not specify a TTL.
TTL (time to live) - The number of seconds a domain name is cached locally before expiration and return to authoritative nameservers for updated information.
Reverse DNS is a method of resolving an IP address into a domain name, just as the domain name system (DNS) resolves domain names into associated IP addresses. One of the applications of reverse DNS is as a spam filter. Typically, a spammer uses an invalid IP address, one that doesn't match the domain name. A reverse DNS lookup program inputs IP addresses of incoming messages to a DNS database. If no valid name is found to match the IP address, the server blocks the message. Reverse DNS is also used for things like network troubleshooting calls (i.e. ping) and monitoring tools.