I know this error is infuriating—you've configured everything right (or so you thought) and the secondary DNS server just won't pull the zone. Let's cut straight to the fix, because 90% of the time it's one of two things.
The Quick Fix
On your primary DNS server (Windows Server or BIND), do these in order:
- Check the zone's serial number. If the secondary's serial is higher than the primary's, transfers get refused with 0X00002618. In Windows DNS, right-click the zone → Properties → Start of Authority (SOA) tab. Bump the serial number up by one (like 2025010101 → 2025010102). In BIND, edit the zone file and increment the serial in the SOA record, then run
rndc reload. - Verify the secondary server is allowed to transfer. On the primary, go to Zone Properties → Zone Transfers tab. Check "Allow zone transfers" and "Only to servers on the following IP addresses." Add the secondary's IP exactly (no trailing spaces, no subnet unless you meant it).
- Test immediately. On the secondary, run
dnscmd /zonerefresh example.com(Windows) orrndc retransfer example.com(BIND). If it still fails, jump to the variations below.
That's it for the common case. Why does this work? The serial number is the trust mechanism—if the secondary thinks it has the same or newer data, it won't accept the transfer. And the ACL check is a security guard that returns this exact error when the IP isn't on the list.
Why the Serial Check Matters
DNS zone transfers use serial numbers to decide if a transfer is needed. When you manually edit a zone file or restore a backup, the serial can get out of sync. The secondary sends its current serial in the SOA query, and if that number is greater than or equal to the primary's, the primary replies with a refusal—which surfaces as 0X00002618 on the secondary's event log. So bumping the serial is the single most common fix, and it costs two seconds.
Less Common Variations
1. Firewall or Network Path Issues
If you've checked the serial and ACLs, look at the network. The error can hide a TCP/UDP port 53 blockage. Run this from the secondary:
nslookup -type=soa example.com 10.0.0.1If that times out, the firewall is blocking. Open TCP 53 (for zone transfers) and UDP 53 (for queries) between the two servers. Windows Firewall on the primary might need a rule if you've recently changed network profiles.
2. Dynamic Updates Throwing Off the SOA
If you have dynamic updates enabled (common with AD-integrated zones), the serial auto-increments on every change. But if you manually edited something and then dynamic updates kicked in, the serial can jump unexpectedly. The fix is to let the system handle serials—don't manually bump if dynamic updates are on, because it can cause a race condition. Instead, just force a reload of the zone after any change.
3. BIND-Specific: Notify and Also-Notify
BIND has a quirk where the secondary won't retry unless it gets a NOTIFY. If your primary is Windows and secondary is BIND, or vice versa, check that notify is set appropriately. On Windows, Zone Properties → Zone Transfers has a checkbox "Notify"—make sure it's checked. On BIND, add also-notify { secondary_ip; }; to the zone block if the secondary isn't in the NS records.
4. Secure Transfers with TSIG
If you're using TSIG, a key mismatch gives this same error. Check that both servers have the same key name and secret. On BIND, use rndc tsig-list to verify. On Windows, it's in the DNS properties under the TSIG tab. A simple typo in the secret is a classic gotcha—I've seen it happen after a config migration.
Prevention Tips
- Use a script to monitor serial consistency. PowerShell's
Get-DnsServerZonecan compare serials between primary and secondary. Schedule it daily. - Document your ACLs. If you add a new DNS server, update the zone transfer allow list on the primary immediately. Half the calls I get involve a forgotten IP.
- Test after any maintenance. Reboot, patch, or config change? Run a manual refresh and watch the event log for 0X00002618 before it becomes a production outage.
- Keep a known-good zone file backup. If you ever corrupt a zone, restore and bump the serial—that's the golden rule.
That's the whole playbook. You'll fix this in under ten minutes, and next time it happens you'll know exactly where to look—I still keep this list in my head after years in the trenches.