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Slow smtp with a 4 - 5 second delay
Question asked by Aftab Hussain - August 6, 2015 at 6:57 AM
Unanswered
I've virtualised a server with SmarterMail 12.5 running on it, the physical server had the following specification:
Dual Core CPU
4GB RAM
1GB NIC, connected to a 10/100 Switch
Sata Drives in RAID 1 Mirror
 
VM - Hyper-V
4 x CPU Cores, much faster Xeon CPU
4GB RAM
1GB physical NIC, 10GB Hyper-V Virtual Switch
SSD Drives in RAID 10
Latest Integration drivers installed.
 
The VM's is running with about 45% of ram being used and less then 10% cpu usage. The IP's on the server have been changed. So its not running out of resources. But I'm seeing a delay when mail is being accepted, one example:
13:40:30 [RemovedIP][63633256] rsp: 220 
13:40:30 [RemovedIP][63633256] connected at 06/08/2015 13:40:30
13:40:30 [RemovedIP][63633256] cmd: EHLO 
13:40:30 [RemovedIP][63633256] rsp: 250- Hello []250-SIZE 52428800250-AUTH LOGIN CRAM-MD5250-8BITMIME250 OK
13:40:30 [RemovedIP][63633256] cmd: AUTH login 
13:40:30 [RemovedIP][63633256] Authenticating as 
13:40:30 [RemovedIP][63633256] rsp: 334 
13:40:30 [RemovedIP][63633256] rsp: 235 Authentication successful
13:40:30 [RemovedIP][63633256] Authenticated as 
13:40:30 [RemovedIP][63633256] cmd: MAIL FROM:<>
13:40:30 [RemovedIP][63633256] rsp: 250 OK <> Sender ok
13:40:30 [RemovedIP][63633256] cmd: RCPT TO:<>
13:40:30 [RemovedIP][63633256] rsp: 250 OK <> Recipient ok
13:40:30 [RemovedIP][63633256] cmd: DATA
13:40:35 [RemovedIP][63633256] rsp: 354 Start mail input; end with <CRLF>.<CRLF>
13:40:35 [RemovedIP][63633256] rsp: 250 OK
13:40:35 [RemovedIP][63633256] Data transfer succeeded, writing mail to 16092784.eml
13:40:35 [RemovedIP][63633256] cmd: MAIL FROM:<>
13:40:35 [RemovedIP][63633256] rsp: 250 OK <> Sender ok
13:40:35 [RemovedIP][63633256] cmd: RCPT TO:<>
13:40:35 [RemovedIP][63633256] rsp: 250 OK <> Recipient ok
13:40:35 [RemovedIP][63633256] cmd: DATA
13:40:39 [RemovedIP][63633256] rsp: 354 Start mail input; end with <CRLF>.<CRLF>
13:40:39 [RemovedIP][63633256] rsp: 250 OK
13:40:39 [RemovedIP][63633256] Data transfer succeeded, writing mail to 16092787.eml
13:41:31 [RemovedIP][63633256] disconnected at 06/08/2015 13:41:31
 
You can see after DATA there is a delay of 4 - 5 seconds, I also just noticed that ~50 seconds for the disconnect at the end, is that normal? I've cleaned up the log, to remove any identifiable information, so <> brackets weren't empty.
 

2 Replies

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Bruce Barnes Replied
January 27, 2016 at 4:10 AM
Not having a reverse DNS for your IP will also get you blocked by lots of MX providers
Bruce Barnes
ChicagoNetTech Inc

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
0
Bruce Barnes Replied
January 27, 2016 at 7:54 AM
That's why all of our hosting contracts include the fact that we handle the customer's DNS servers for them.
 
Mail servers, IIS, and DNS have become so complicated that the simplest mistake can stop delivery and function completely.   By having us handle all of the technical aspects of their hosting requirements, we're in a position to both:
 
  • monitor and control - before it becomes an emergency
  • troubleshoot without having to disrupt the customer's schedule
  • provide the latest stable releases of the products which the customer is running
  • do the required work without having to check with the customer on every detail
  • spend a lot less time resolving crises
  • monitor the expiration of their domain names and either renew them for them or remind them to do so
 
Without making an editorial comment on anyone's intelligence, and with all due respect for customers, both our current, and future, the reason the reason customers usually come to us is because they are either uncomfortable working with the detail required for the hosted services and/or DNS, or they have botched them up in the past and it cost them a lot of time or money.  They are specialists in their fields of work and expertise, and we in ours.
 
Bruce Barnes
ChicagoNetTech Inc

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

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