Hi, Is there similar problem existing with sending email to email server inside china? maybe you could check end-to-end delay and packet loss rate. Another method, ask your customer to cut the attachment to several parts and send them seperately. Joe --- Lou Laczo <llaczo@inetu.net> wrote:
Hi all,
I did a quick search of the archives and was unable to find any previous discussions relevant to this topic.
One of our clients has been having problems receiving some legitmate emails from business associates in China. The client's mailserver is running qmail. In almost all of the cases, the failing email has at least one attachment and is larger than what might be considered "normal". Our client's mailserver receives part of the message and then the smtp connection hangs and eventyally times out. Many times, the sending mail server will attempt to send the message again and again before finally giving up. The failing messages can be successfully delivered to hotmail and/or yahoo accounts.
I've observed this problem while it was occuring and there are multiple smtp connections open between the clients server and the sender's server. The connections are in various states, some established, some in fin_wait, etc. I've tried tracerouting to the sender's server and in every case I've observed the trace times are terrible. I've looked at various aspects of the mail server's configuration and all looks well there. I've even tried having the senders email to a totally different mailserver on our network and get similar failures. It's staring to look like this is just a simple case of bad network connectivity from the sender. My guess is that the big free email systems have relay servers all over the world, so the sender in China would be talking to a server much closer to home. This would explain why the mail can be successfully delivered to hotmail, yahoo, etc.
Has anyone ever experienced a problem similar to this? Thanks in advance for your attention and any responses/help.
--Lou.
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