long delay after invoking web service until SOAP message is sent

[beachdog]

I have built a web service consumer application by adding a web
reference for a vendor-provided wsdl file. My client is
interoperating with the server just fine, in terms of sending a
request and receiving and properly parsing a response, but the problem
is that when I step through it in the debugger (or even when I run the
executable) there is a delay of about 15 seconds after executing my
XXXAsync method to invoke the web service until the SOAP request
message is actually sent out over the wire. I have no idea what the
program is doing during this time. Anyone have an idea of what might
be causing the delay? It almost seems like the web consumer is trying
to resolve some dns names or something, but I have set the url to send
to to be a specific ip address so there is no need for dns there. My
client PC is also connecting to the server over a VPN, not sure if
that plays into this somehow.

I have taken an ethereal trace during this time to see what is going
over the network during this 15 second delay, and what I see is a
bunch of SMB messages that Ethereal decodes as Trans2 requests and
responses, followed 12 seconds later by some Netbios name queries,
followed at about the 15 second interval by the SOAP message.

[John Saunders [MVP]]

"beachdog" <dh*****@pactol us.comwrote in message
news:11******** *************@y 80g2000hsf.goog legroups.com...

>I have built a web service consumer application by adding a web
reference for a vendor-provided wsdl file. My client is
interoperating with the server just fine, in terms of sending a
request and receiving and properly parsing a response, but the problem
is that when I step through it in the debugger (or even when I run the
executable) there is a delay of about 15 seconds after executing my
XXXAsync method to invoke the web service until the SOAP request
message is actually sent out over the wire. I have no idea what the
program is doing during this time. Anyone have an idea of what might
be causing the delay? It almost seems like the web consumer is trying
to resolve some dns names or something, but I have set the url to send
to to be a specific ip address so there is no need for dns there. My
client PC is also connecting to the server over a VPN, not sure if
that plays into this somehow.

I have taken an ethereal trace during this time to see what is going
over the network during this 15 second delay, and what I see is a
bunch of SMB messages that Ethereal decodes as Trans2 requests and
responses, followed 12 seconds later by some Netbios name queries,
followed at about the 15 second interval by the SOAP message.

To whom are these SMB messages directed? What resource are they about? That
may give you a clue as to what's going on.

This isn't standard web services behavior, so it's likely to be something
specific to your environment; perhaps something to do with anti-virus
software, or some other piece of code that thinks it's a good idea to delay
you for 15 seconds while you're in the debugger.
--

John Saunders [MVP]

[beachdog]

Interesting, it looks like the delay was caused by web proxy auto-
discovery. I brought up IE, went into Tools/Internet Options/
Connections/LAN Settings and unchecked "Automatica lly Detect
Settings", and with that one change now the delay is gone. Also, if I
take an Ethereal trace now, what is different is that I no longer see
the broadcast messages of netbios name queries to WPAD.MSHOME. (It
looks like the SMB messages were a red herring as I now see that those
occur at times when I am not running my tests and must therefore be
unrelated).