Building The Dream

Forgive my sincere title above. I don’t find more suitable title for my experience below.

I was asked to send email on behalf of my boss to his business colleague. Yes, It was common actually since he doesn’t much care about Internet technology anyway. But, this one was bit different. He asked me to send email using Yahoo! mail service, not using our company mail service. I didn’t had chance to argue when he said that sometimes when using our own mail service, it takes so long to be received to whom it was intended to. Maybe that’s true, but sometimes people tend to broader and generalize simple problems into bigger ones. Maybe he read my mind at that time, so he told me to send it both using Yahoo!mail service and our company mail service.

I did both. The email’s attachment was quite big, around 10 MB and contained 11 files. I sent it once each ways (by using Yahoo! mail service and our company mail service). It took no longer and after waiting a while, I didn’t received any confirmation that the delivery of the email failed somehow. I rechecked it in my mail server log, and didn’t find any error message regarding the email. Hmm… everything works as usual, I thought.

One day after, he phoned me saying that his colleague didn’t receive the email yet. He asked to sent it once more by separating the attachments into one attachment in one delivery. I said OK, although I wondered what was going wrong. Then I checked it. First my mail server log.

I’m using Postfix as MTA. And I also have pflogsumm to summarize mail server log more readable. Here is the screenshot.

Ok, as you can see from the picture, the email should be delivered successfully. Then, I checked to the company mail server seeing how many bytes the can receive for one email. I did the following command in shell.

> host -t MX fmi.com
fmi.com mail is handled by 10 mail.phelpsd.com.
> telnet mail.phelpsd.com 25
Trying 198.176.208.5…
Connected to mail.phelpsd.com.
Escape character is ‘^]’.
220 mail.phelpsd.com Service ready
EHLO mail.phelpsd.com
250-mail.phelpsd.com Hello
250-DSN
250 SIZE 31457280
QUIT
221 mail.phelpsd.com Service closing connection
Connection closed by foreign host.

The size is 31457280, that is 30MB, so I assumes that it can received email up to 30MB.

Because Yahoo didn’t complained about the email size, I think it should be delivered to mail.phelpsd.com successfully. Then, I followed up to the next.

My company is connected to the Internet using our University link. Don’t get confused. My company is owned by our university(and I’m still a student though ). I searched mail queue that can be seen from our University monitoring website and found that there were 9 queues to destination @fmi.com. I didn’t find a chance to ask University’s mail administrator, so I just checked the SMTP gateway how many bytes it can received for attachment.

xxx@xxx>telnet mx.yahoo.com 25
Trying 68.142.195.60…
Connected to hp.latam.yahoo4.akadns.net.
Escape character is ‘^]’.
220 SMTP GATEWAY INTERNAL mx4.xxx.id ESMTP
EHLO mx4.xxx.id
250-mx4.xxx.id
250-PIPELINING
250-SIZE 50000000
250-VRFY
250-ETRN
250-STARTTLS
250-AUTH LOGIN PLAIN
250-AUTH=LOGIN PLAIN
250 8BITMIME
QUIT
221 Bye
Connection closed by foreign host.

Hmm…50,000,000 bytes, of course it will pass, I thought.

Then, what went wrong ? I don’t know. I think, maybe it is more difficult to download such a big attachment than saying “I didn’t receive the email yet, please send it again!”. Or maybe there was system error at their network so they couldn’t download the email nor its attachments.

Or maybe I was the one who was wrong by sending such a big attachment in one delivery. I stupidly assumed that the system was reliable so It doesn’t matter how big the attachment as long as it doesn’t violate the system policy.

Moral of the story ? Read the title !