Remote host said: 553 sorry, invalid HELO hostname (#5.7.1)

Problem reported by Abhishek Khariyal - 12/23/2014 at 11:09 AM

Submitted

We are using smartermail 11.6. We are not able to send mails to rediff.com and get follwing error :-

Could not deliver message to the following recipient(s):

Failed Recipient: "xyz@rediffmail.com"
Reason: Remote host said: 553 sorry, invalid HELO hostname (#5.7.1)
 

   -- The header and top 20 lines of the message follows --

Received: by Autocad_2013 via HTTP

I am able to resolve the DNS queries for our domain. Both forward and reverse lookup for our mx record are showing up. We have configured Barracuda Anti Spam as our MX record.

Also a health check up of our domain shows below mentioned error :-

https	xyz.com	The remote name could not be resolved: 'xyz.com' (https://xyz.com)

Your help would be appreciated.

6 Replies

Reply to Thread

Bruce Barnes Replied

12/23/2014 at 11:23 AM

There's not enough information to help you. Post your actual domain.

Bruce Barnes ChicagoNetTech Inc brucecnt@comcast.net Phonr: (773) 491-9019 Phone: (224) 444-0169 E-Mail and DNS Security Specialist Network Security Specialist Customer Service Portal: https://portal.chicagonettech.com Website: https://www.ChicagoNetTech.com Security Blog: http://networkbastion.blogspot.com/ Web and E-Mail Hosting, E-Mail Security and Consulting

Scarab Replied

12/23/2014 at 11:26 AM

Abhishek,

What do you have set in SmarterMail under SETTINGS > GENERAL SETTINGS > SERVER INFO > HOSTNAME?

If other major providers, especially AOL.com and Yahoo.com, are accepting your emails then most likely your Hostname is a valid FQDN (Fully Qualified Domain Name) and matches a FCrDNS (Forward Confirmed Reverse Domain Name Service) lookup, in which case it could be a temporal problem with REDIFF.COM's DNS Servers not being able to do these lookups for some reason.

I have seen this problem arise when we have blocked entire Class C (or higher) IP Ranges at our Firewall. If an IP of their DNS Server(s) is blocked from making DNS queries to your DNS Servers that are authoritative for your domain then the result would be a 553 response code.