Cisco Cisco Email Security Appliance C160 Mode D'Emploi

 

Choose Mail Policies > Signing Profiles.

In the Domain Signing Profiles section, in the DNS Text Record column, click the Generate link for the 
corresponding domain profile. 

Mark the checkbox for the attributes you wish to include in the DNS text record.

Click Generate Again to re-generate the key with any changes you have made.

The DNS text record is displayed in the text field at the bottom of the window (where you can now copy 
it). In some cases, multi-string DNS text records are generated. See 

Click Done.

Multi-string DNS text records may be generated if the key size of the signing key used to generate the 
DNS text records are larger than 1024 bits. This is because not more than 255 characters are allowed in 
a single string of a DNS text record. The DKIM authentication may fail as some of the DNS servers do 
not accept or serve multi-string DNS text records. 

To avoid this scenario, it is recommended that you use double quotes to break up the multi-string DNS 
text record into smaller strings not exceeding 255 bytes. The following is an example.

s._domainkey.domain.com. IN TXT "v=DKIM1;" 

"p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQE"

"A4Vbhjq2n/3DbEk6EHdeVXlIXFT7OEl81amoZLbvwMX+bej"

"CdxcsFV3uS7G8oOJSWBP0z++nTQmy9ZDWfaiopU6k7tzoi"

"+oRDlKkhCQrM4oP2B2F5sTDkYwPY3Pen2jgC2OgbPnbo3o"

"m3c1wMWgSoZxoZUE4ly5kPuK9fTtpeJHNiZAqkFICiev4yrkL"

"R+SmFsJn9MYH5+lchyZ74BVm+16Xq2mptWXEwpiwOxWI"

"YHXsZo2zRjedrQ45vmgb8xUx5ioYY9/yBLHudGc+GUKTj1i4"

"mQg48yCD/HVNfsSRXaPinliEkypH9cSnvgvWuIYUQz0dHU;" 

DKIM implementations reassemble DNS text records broken down this way into the full original single 
string before processing them.

Once you have created a signing key, associated it with a domain profile, and generated and inserted the 
DNS text into your authorized DNS, you can test your domain profile. 

Choose Mail Policies > Signing Profiles.