DNS records for load balancing
When you create a load balancer , Cloudflare automatically creates an LB DNS record for the specified Hostname. This functionality allows you to use a hostname with or without an existing DNS record.
Supported records
For customers on non-Enterprise plans, Cloudflare supports load balancing for A
, AAAA
, and CNAME
records.
For customers on Enterprise plans, Cloudflare supports load balancing for A
, AAAA
, CNAME
, MX, SRV, and TXT records.
Priority order
For hostnames with existing DNS records, the LB record takes precedence when it is more or equally specific:
Scenario 1:
- A, AAAA, or CNAME:
x.example.com
- LB record:
x.example.com
- Outcome: LB record takes precedence because it is as specific as the DNS record.
- A, AAAA, or CNAME:
Scenario 2:
- A, AAAA, or CNAME:
y.example.com
- LB record:
*.example.com
(wildcard record) - Outcome: DNS record takes precedence because it is more specific.
- A, AAAA, or CNAME:
Scenario 3:
- A, AAAA, or CNAME:
*.example.com
- LB record:
*.example.com
- Outcome: LB record takes precedence because it is as specific as the DNS record.
- A, AAAA, or CNAME:
Disabling a load balancer
When you disable a load balancer, requests to a specific hostname depend on your existing DNS records:
- If you have existing DNS records, these records will be served.
- If there are no existing records, requests to the hostname will fail.
In both cases, disabling your load balancer prevents traffic from going to any associated origin or fallback pools.
SSL/TLS coverage
Due to internal limitations, Cloudflare Universal SSL certificates do not cover load balancing hostnames by default. This behavior will be corrected in the future.
As a current workaround for a domain or first-level subdomain (lb.example.com
), create a proxied CNAME
/A
/AAAA
record for that hostname.
For example, if your load balancer hostname was lb.example.com
, you could create the following record solely for the purpose of SSL/TLS coverage.
Type | LB | IPv4 address | Proxy status |
---|---|---|---|
A | www | 192.0.2.1 | Proxied |
Based on the priority order , it would not receive any traffic because it is as equally specific as the LB hostname.
To get coverage for any deeper subdomain (lb.dev.example.com
), purchase an advanced certificate
.