Emails with attachements that wont 'go'

[Simone Nelson]

In the past few weeks I have wanted to send many emails with simple .doc
attachements that have refused to 'go'. I do know all about .exe extensions
etc and mostly zip anything potentially harmful or big - but if they are
relatively small and totally harmless why will the email not go?

I regularly send emails with small attachements, like pictures of colours or
instructions for use.

 

[neo [mvp outlook]]

What type of e-mail account are you working with? (e.g. POP3/IMAP/Microsoft
Exchange, .etc)

When you click send, what happens? (e.g. If Outlook gives an error message,
what does the text say?)

What operating system are you using?

What version of Microsoft Outlook are you using?

What type network connection are you using? (e.g. Dialup, Broadband, .etc.
If Broadband, are you behind a personal router that lets you share a single
IP address to many machines. Also don't forget to mention if it is a
wireless connection to the personal router.)

 

[Simone Nelson]

I will reply appropriately inbetween.....

What type of e-mail account are you working with? (e.g. POP3/IMAP/Microsoft
Exchange, .etc)
POP3

When you click send, what happens? (e.g. If Outlook gives an error message,
what does the text say?)

No Error message just sits there

What operating system are you using?

Windows XP - Office Professional 2003, So Outlook 2003 with all updates
automatiocally and SP3

What version of Microsoft Outlook are you using?

See above

What type network connection are you using? (e.g. Dialup, Broadband, .etc.
If Broadband, are you behind a personal router that lets you share a single
IP address to many machines. Also don't forget to mention if it is a
wireless connection to the personal router.)

Could this be the nitty gritty question?!?!?

*I have broadband via a wireless connection to the nearest ADSL - operates
at around 400kps.
*There is a router at my neighbours end which connects to the wireless for
me and then at this end it is connected to my server - Server 2003, This
wireless 'box' is only capable of being connected one PC - hence.....
*but there is a switch for my network which is also connected to the server.
*My neighbour has her own IP address,
*all my PCs and Printers have their own IP addresses

 

[neo [mvp outlook]]

For the nitty-gritty... yep, if you notice this for most/all messages with
attachments sitting in your outbox. Open a command prompt and try the
following with the name of your ISP mail server.

ping isp.mail.server.name -f -l 1472

does it come back with...

packet needs to be fragmented but DF set

If yes, then you need to test with a smaller number. For example...

ping isp.mail.server.name -f -l 1462



Once you find the magic number, you might have to change your MTU*. The MTU
value will be the max ping size + 28. (You should never have to go below
512 for a wired/wireless ethernet connection. You want this value as big as
possible because it will impact your up/download speeds.)

/neo

* Use google to search for windows xp mtu. lots of sites describe the
process

PS - If you let Outlook sit long enough, you should get an error message
about a timeout error. I think Outlook's default for SMTP is 1 minute with
a max of 5.

 

[Mike4QL]

I'm wondering how helpful this test is going to be.

First of all if the MTU is already set too low this test will simply show
the MTU setting and you will be no further ahead. Surely you need to make
sure the MTU is at (say) 1500 before you try this?

Secondly the problem is the email messages _never_ go. Perhaps I am wrong
but I would have thought if the MTU was set too high you would just get a lot
of fragmented packets and the message may take a long time to send but it
would eventually go.

I have seen this problem with Outlook occassionally although I had never
pinned it down to a particular size or type of message. In my case the
message would sit in the Outbox for days and would never be sent. It does
not seemed to have happened much (if at all) since I moved up to Outlook 2007.

Mike

 

[neo [mvp outlook]]

For Microsoft operating systems have preset defaults for certain types of
network connections and I always assume that users don't change away from
the out-of-box configuration. If curious what the default MTU settings are,
please see:

http://support.microsoft.com/kb/314496/EN-US/
http://support.microsoft.com/kb/140375/EN-US/


I think it is helpful to have users check this especially on broadband
connections. The reason why is that more or more are sitting behind a soho
router that could be the problem. For example, from router to ISP could be
a PPoE connection that has an MTU of 1492. However the connection from PC
to router is an MTU of 1500. Rather than letting every packet be
fragmented, it would be better to know this and lower the MTU in the
operating system to match the SOHO router.

 

[Mike4QL]

Absolutely correct and many will enjoy improved speed by reducing the MTU as
you have described.

But, this doesn't explain why an email _never_ gets sent and does not time
out. It just sits in the Outbox for days and sometimes weeks.

 

[neo [mvp outlook]]

In which case I would rule out the obvious things like...

1) Is Outlook starting up on offline mode?

2) If Outlook is offline, is the send/receive group configured to send items
while "offline"? (For example, Outlook 2003 will send items while offline if
the F9 key is pressed, but won't do it automagically unless settings are
changed in the send/receive group.)