Domain Name Processing Problem

[141499-LHSFK]

Type: Bug Fix + Feature Enhancement
Version: 1.5
Affected Scope: Third-level domain handling, DNS record verification logic, TXT record customization
Core Problem Description:

1.DKIM Record Truncation Error

    Symptom: After adding domain mail.example.com, the generated DKIM record shows d=example.com (incorrectly truncated to second-level domain).

    Consequence: DKIM validation fails.

2.DNS Record Display Anomalies

    Problem A: DNS resolves correctly, but system displays "Not Set".

    Problem B: After clicking "Verify DNS Settings", all record values erroneously duplicate subdomains:

   - Original  Records (Content A)
   + After clicking the Verify button  Records (Content B)

 		Content A:
	```
	记录类型	主机记录	记录值
	A	mail.example.com	1.1.1.1

	记录类型	主机记录	记录值	MX优先级
	MX	@	mail.example.com	10

	记录类型	主机记录	记录值
	TXT	@	v=spf1 +a +mx +ip4:1.1.1.1 -all复制
	TXT	default._domainkey	v=DKIM1;k=rsa;p=MIGfMA0GCS.... 复制
	TXT	_dmarc	v=DMARC1;p=quarantine;rua=mailto:admin@example.com 复制
	```

	Content B:
	```
	记录类型	主机记录	记录值
	A	mail.mail.example.com	1.1.1.1
	步骤2：添加MX记录
	记录类型	主机记录	记录值	MX优先级
	MX	@	mail.mail.example.com	10
	步骤3：添加TXT记录
	记录类型	主机记录	记录值
	TXT	@	v=spf1 +a +mx +ip4:1.1.1.1 -all复制
	TXT	default._domainkey	v=DKIM1;k=rsa;p=MIGfMA0GCS.... 复制
	TXT	_dmarc	v=DMARC1;p=quarantine;rua=mailto:admin@mail.example.com 复制
	```

        Impact: MX/SPF/DKIM/DMARC validation completely fails due to invalid host records.
    
    3.Lack of TXT Record Customization
    
        Current SPF/DMARC records use rigid templates.
    
        Cannot flexibly adjust fields (e.g., SPF mechanisms, DMARC policies).

[dreambladeflag]

No, we do not recommend using mail.example.com for your domains because it conflicts with the MX hostname (we default to 'mail.your_domain_name' as the MX record).

[141499-LHSFK]

Uh, I noticed that there are many places in the code that are hard-coded. This is not realistic, right? If you must hard-code, wouldn't it be better to use the prefix "mx" as the mx record in the code and leave "mail" to the web? Most cloud vendors seem to use "mx+sequence number" as the mx record.

[141499-LHSFK]

I changed the domain name to a third-level domain name that does not start with "mail", but the "d=" in the DKIM signature will still be truncated to the second-level domain name.