Ethernet LAN slow smtp issue/packet capture

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Subject Author Date
slow smtp issue/packet capture glnsk8ter 12-18-06
Posted by glnsk8ter on December 18, 2006, 10:24 am
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I am trying to diagnose a slow email issue from various office scanners that
can perform scan to email from their control panel, used to work fine now
their is an intermittent situation where scan a page once, goes fine, rescan
it again and it may take minutes or hours. local email server. I have a
packet capture, but I just noticed there doesn't seem to be a way to attach
it.

I see
sections where
a previous segment loss message from is sent from scanner.
then an awk from email server
then some packets of message body (varies from 3 to 7)
then duplicate awk packets equal in quanity to the number of message body
packet sent.
then a single fast retransimission of message body from scanner is sent to
email server
then more packets without any issues, then then the whole set of messages
above again.


Posted by on December 26, 2006, 10:39 am
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glnsk8ter wrote:
> I am trying to diagnose a slow email issue from various office scanners that
> can perform scan to email from their control panel, used to work fine now
> their is an intermittent situation where scan a page once, goes fine, rescan
> it again and it may take minutes or hours. local email server. I have a
> packet capture, but I just noticed there doesn't seem to be a way to attach
> it.
>
> I see
> sections where
> a previous segment loss message from is sent from scanner.
> then an awk from email server
> then some packets of message body (varies from 3 to 7)
> then duplicate awk packets equal in quanity to the number of message body
> packet sent.
> then a single fast retransimission of message body from scanner is sent to
> email server
> then more packets without any issues, then then the whole set of messages
> above again.

In a modern ethernet network the most likely cause is
a duplex missmatch.

Set everything to auto speed/auto duplex and try again.

Check all interfaces for hardware layer errors CRC, align/frame,
short.

If you have unmanaged network equipment check the end stations.
"netstat -e" works sometimes - If that doesn't identify the issue
get managed network equipment or randomly change things
until it goes away.

Second most likely is bad cable or NIC.


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