IIS 5 & IIS 6
SMTP refusing incoming connections
Last post Jun 03, 2010 11:48 AM by Rovastar
Jun 01, 2010 06:55 AM|spawn3010|LINK
I am facing some problem with my SMTP server using IIS 6.0 , running Windows 2003 SP2
My Smtp server send and receives emails from my anti-spam and anti-virus vendor.
So the connections is established between my windows SMTP and the vendors Qmail (Linux based SMTP)
Mostly in the mornings whenever the vendors smtp tries to send any emails to my SMTP, they are getting the message
"2010-04-28 09:48:19.061715500 delivery 16599: deferral: Sorry,_I_wasn't_able_to_establish_an_SMTP_connection._(#4.4.1)/"
I then have to do a telnet to their SMTP server and after doing this for a few minutes, i then start receiving emails.
I troubleshooted and disabled the power management option for the network adaptor , but still every morning , the first few mails are getting delayed and then throughout the day there is no delay at all.
I have enabled logging in SMTP but i am unable to see any reasons as to why the connections are being refused.
I have configured the server for unlimited connections.
Please advise and let me know what i need to do so that no connections are dropped.
Thanks in advance for helping
Jun 02, 2010 08:58 AM|Rovastar|LINK
You are using IISs SMTP to receive mail?!??!
This is not really advisable and you should look at using a proper mail server for this task.
Even with that said it looks like a network issue. Gt a packet sniffer on there to get more information about what the delay occurs.
Jun 03, 2010 12:32 AM|spawn3010|LINK
Thanks for your reply.
I have a Lotus Domino Server as my email server.
In between my Lotus server and my anti-spam vendor, I have kept an intermediate IIS SMTP to avoid my lotus server from being exposed to the net.
So outgoing mails have the following path
My Lotus SMTP -->My IIS SMTP --> AntiSpam vendor SMTP --> Cloud
My MX is pointed to the antispam vendor, so the Incoming mails have the following path
Cloud--> AntiSpam vendor SMTP-->My IIS SMTP --> My Lotus SMTP
I have tried to check for hits on my firewall. but nothing is getting blocked.
I am unable to understand what could be the reason for my SMTP refusing connections to my anti-spam vendor
Jun 03, 2010 11:48 AM|Rovastar|LINK
Packet sniff it out