--- title: "How to Set Up Reverse DNS (PTR) for a Mail Server" description: "Set PTR records for your IPv4 and IPv6 addresses in the client area, make them forward-confirmed for reliable email delivery, and verify them with dig." url: "https://powerdedi.com/docs/reverse-dns" last_updated: "2026-09-25" publisher: "PowerDedi (https://powerdedi.com)" --- # Set up reverse DNS (PTR records) Point your IP addresses back to a hostname from the Network tab, then verify forward-confirmed reverse DNS with dig. Updated September 25, 2026 · 3 min read · 7 sections ### All guides Filter the guides ### Getting started - [Get started with your dedicated server](https://powerdedi.com/docs/getting-started) ### Server management - [Use the IPMI/KVM console](https://powerdedi.com/docs/ipmi-kvm-console) - [Reinstall the operating system](https://powerdedi.com/docs/reinstall-os) - [Repair your server with rescue mode](https://powerdedi.com/docs/rescue-mode) - [Monitor and repair software RAID](https://powerdedi.com/docs/software-raid) ### Networking - [Configure IPv6 on your server](https://powerdedi.com/docs/ipv6-configuration) - [Test your server’s network speed](https://powerdedi.com/docs/network-speed-test) - [Set up reverse DNS (PTR records)](https://powerdedi.com/docs/reverse-dns) ### Billing - [Pay with cryptocurrency](https://powerdedi.com/docs/pay-with-crypto) ### Security - [Secure your server in the first hour](https://powerdedi.com/docs/secure-your-server) - [Create and use SSH keys](https://powerdedi.com/docs/ssh-keys) Reverse DNS maps an IP address back to a hostname. You’ll set PTR records for your server’s addresses in the client area and make sure they match your forward DNS. You need a domain name whose DNS records you can edit. ## What a PTR record is A forward lookup turns `mail.example.com` into `203.0.113.10` through an A record, or an AAAA record for IPv6. A reverse lookup does the opposite: resolvers ask for `10.113.0.203.in-addr.arpa`, or a long name under `ip6.arpa` for IPv6, and get a PTR record back. Reverse zones belong to whoever holds the address space, so you set PTR records for PowerDedi addresses in our client area, not at your DNS provider. ## Why mail servers need it Receiving mail servers treat reverse DNS as a basic trust signal. Gmail’s [email sender guidelines](https://support.google.com/a/answer/81126) require the sending IP address to have a PTR record whose hostname resolves back to that same address through its A or AAAA record. This is called forward-confirmed reverse DNS (FCrDNS). Other large mailbox providers run similar checks, and mail from addresses without it is often rejected or filed as spam. The same applies to IPv6. If your mail server can send over IPv6, its IPv6 address needs a matching PTR and AAAA record; otherwise, configure the mail server to send over IPv4 only. Beyond email, reverse DNS makes logs, traceroutes and abuse reports easier to read. ## Choose a hostname - Use a fully qualified name in a domain you control, such as `srv1.example.com` or `mail.example.com`. - Name the host that really uses the address. For a mail server, use the name it announces in its SMTP greeting (HELO or EHLO). - Avoid names that look residential, such as names containing the IP address or words like “dynamic” or “pool”: spam filters penalize them. - Set exactly one PTR record per address. ## Set the PTR records 1. At your DNS provider, create the forward records first: an A record for `mail.example.com` pointing to `203.0.113.10` and, if you use IPv6, an AAAA record pointing to `2001:db8:1234:5678::2`. 2. In the client area, open **Servers**, select the server and open the **Network** tab. 3. Next to the IPv4 address, enter the hostname and save. 4. For IPv6, enter the full address you use, such as `2001:db8:1234:5678::2`, together with its hostname. Repeat for each IPv6 address that needs a name. Each record shows **Pending** until our network team publishes it, then **Active**. Allow for DNS caches on top of that. ## Verify with dig ```bash dig -x 203.0.113.10 +short dig -x 2001:db8:1234:5678::2 +short dig mail.example.com A +short dig mail.example.com AAAA +short ``` The first two commands should print `mail.example.com.` and the last two the addresses you started from. When both directions match, your reverse DNS is forward-confirmed. `dig` is in the `bind9-dnsutils` package on Debian and Ubuntu, and in `bind-utils` on AlmaLinux and Rocky Linux. ## Propagation and caching Resolvers cache each answer for the record’s TTL (time to live). A resolver that looked up your address before the change keeps the old answer, or the old “no such record” answer, until that TTL expires. That is why one tool may already show the new name while another still shows the old one. To see the authoritative answer without caches, follow the delegation from the root servers: ```bash dig -x 203.0.113.10 +trace ``` If the authoritative answer is correct, wait for caches to expire. If it is still wrong or missing an hour after your change, check the entry in the **Network** tab, then open a support ticket. ## If mail is still rejected Reverse DNS is only one of the checks. Gmail also requires SPF or DKIM authentication from every sender, and DMARC from bulk senders. Read the bounce message first: it usually names the check that failed. Then confirm that your mail server announces the same hostname as its PTR record, and that it only sends over IPv6 from an address with matching PTR and AAAA records. [← Previous **Test your server’s network speed**](https://powerdedi.com/docs/network-speed-test) [Next → **Pay with cryptocurrency**](https://powerdedi.com/docs/pay-with-crypto) **Still stuck?** Customers with an active server open a support ticket: tell us what you tried and an engineer takes it from there, usually within a few hours. [Open a ticket](https://powerdedi.com/account/support) ## Related guides [All guides](https://powerdedi.com/docs) [Networking](https://powerdedi.com/docs/category/networking) Updated September 25, 2026 ### [Configure IPv6 on your server](https://powerdedi.com/docs/ipv6-configuration) Put your routed /64 to work: pick an address, set the fe80::1 gateway, test connectivity and add more addresses. 3 min read [Networking](https://powerdedi.com/docs/category/networking) Updated September 25, 2026 ### [Test your server’s network speed](https://powerdedi.com/docs/network-speed-test) Measure a 10 Gbps port properly: multi-stream iperf3, nearby targets, basic TCP tuning and what to send support. 4 min read [Getting started](https://powerdedi.com/docs/category/getting-started) Updated September 26, 2026 ### [Get started with your dedicated server](https://powerdedi.com/docs/getting-started) From order to first SSH login: choose a server, pay in crypto, connect, then run the first-ten-minutes checklist. 4 min read --- PowerDedi — Dedicated servers with 10 Gbps unmetered, paid in crypto. 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