[Techtalk] Null connections with sendmail?

[Michelle Murrain]

At 05:18 PM 4/1/2002, Raven, corporate courtesan wrote:
>         So first, check out the connectivity on your new network.  It's
>possible that these connections are being dropped between the time when
>they were opened and the time when they were (supposed to) send mail to
>you.  Tcpdump it if you have to -- you should see the drops and the
>retransmissions.

I did a tcpdump dst host (myhostname):

How do you see drops and re-transmissions?  I've seen entries like:

  ns6.choiceone.net.domain > nanuuq.ursa-minor.com.4851: 5683 ServFail 
0/0/0 (46) (DF)
192.168.1.1 > nanuuq.ursa-minor.com: icmp: net 
w058.z065105051.bwi-md.dsl.cnc.net unreachable

What do these mean?

What I'm doing now is taking a big tcpdump run, and then I'll try to 
correlate the tcpdumps with my mail log file, and see if there is a pattern.

.Michelle

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Michelle Murrain
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