Email Security.cloud infrastructure is blocklisted

Products

• Email Security.cloud

Issue/Introduction

 

Resolution

1. Email Security.cloud Email infrastructure may get blacklisted from time to time. This is due to abused user accounts or compromised servers relaying spam through Broadcom's infrastructure. This may cause the Broadcom Email Security.cloud IPs to be blocked by various lists.
    
2. Email Security.cloud does Outbound Spam Scanning for every email that passes through the email security.cloud Infrastructure and rejects the emails that are identified as spam in order to provide continuity of service. Keep in mind that the Outbound spam scanning is more lenient to reduce the amount of false positive that could impact our customers.
    
3. Broadcom does monitor blocklists regularly and where possible requests de-listing immediately.
    
4. If it is believed the blocklisting is causing an issue for specific messages, provide examples of failed messages to confirm that there is a connection to the specific blocklist. It is very common for users to see an email fail and then do a blocklist check and assume that must be the reason, even if the message reported by the recipient system doesn't indicate that is the cause for the rejection or even specifically reports a different issue entirely.
    
5. It is not uncommon for a recipient mail server to continue rejecting messages for a short time even after we have confirmed the de-listing.  This usually due to a blocklist being cached locally for a period of time.
    
6. All blocklists are not created equal.  Some may have slower policies for de-listing. Therefore, Broadcom needs to wait the time period to be removed from the specific blocklist.
    
7. Additionally, some lists may charge for de-listing, Broadcom WILL NOT honor this and make such payments as section 2.2.5 of RFC 6471 specifically forbids charging for de-listing and recommends that such lists should not be used.
    
   • "Therefore, negative-connotation DNSBLs MUST not charge fees or require donations for de-listing or "faster handling", and it is RECOMMENDED that such DNSBLs that do charge fees or require donations not be used."
      
   • If a recipient organization is making use of such a list, we recommend providing them with this information and suggesting a better list might be used such as:
      
     • sbl.spamhaus.org (SBL)
     • xbl.spamhaus.org (XBL)
     • dbl.spamhaus.org (DBL)
     • cbl.abuseat.org (CBL)
     • SpamCop (SCBL)