I have the following code:
Dim IP, domainName As String
domainName = "yahoo.com"
Try
IP = System.Net.Dns. GetHostByName(d omainName).Addr essList(0).ToSt ring()
Catch ex As Exception
IP = "Not Valid"
End Try
Console.WriteLi ne(IP)
System.Threadin g.Thread.Sleep( 2000)
When it has a resolvable domain, like yahoo.com it responds back instantly
with the ip address. However, if there is a domain in there that does not
exist, like blue2343.com, it takes upwards of 5 seconds to print "Not Valid"
to the screen. Why is that? and is there a way around it?
Thanks,
Scott
22  1560 
Scot,
This is mostly likely due to the time it is taking for your DNS server to
attempt to resolve the DNS name to an IP address. It is not uncommon for
3-6 seconds to pass while DNS attempts to resolve an entry that does not
exist. There is no way around the time it takes for a DNS server to exhaust
its resources in an attempt to resolve hostnames to ip addresses.
HTH,
Raymond Lewallen
"Scot" <bl***@blank.bl ank.com> wrote in message
news:c5******** @library1.airne ws.net... I have the following code:
Dim IP, domainName As String
domainName = "yahoo.com"
Try
IP =
System.Net.Dns. GetHostByName(d omainName).Addr essList(0).ToSt ring() Catch ex As Exception
IP = "Not Valid"
End Try
Console.WriteLi ne(IP)
System.Threadin g.Thread.Sleep( 2000)
When it has a resolvable domain, like yahoo.com it responds back instantly
with the ip address. However, if there is a domain in there that does not
exist, like blue2343.com, it takes upwards of 5 seconds to print "Not
Valid" to the screen. Why is that? and is there a way around it?
Thanks,
Scott
Scot,
This is mostly likely due to the time it is taking for your DNS server to
attempt to resolve the DNS name to an IP address. It is not uncommon for
3-6 seconds to pass while DNS attempts to resolve an entry that does not
exist. There is no way around the time it takes for a DNS server to exhaust
its resources in an attempt to resolve hostnames to ip addresses.
HTH,
Raymond Lewallen
"Scot" <bl***@blank.bl ank.com> wrote in message
news:c5******** @library1.airne ws.net... I have the following code:
Dim IP, domainName As String
domainName = "yahoo.com"
Try
IP =
System.Net.Dns. GetHostByName(d omainName).Addr essList(0).ToSt ring() Catch ex As Exception
IP = "Not Valid"
End Try
Console.WriteLi ne(IP)
System.Threadin g.Thread.Sleep( 2000)
When it has a resolvable domain, like yahoo.com it responds back instantly
with the ip address. However, if there is a domain in there that does not
exist, like blue2343.com, it takes upwards of 5 seconds to print "Not
Valid" to the screen. Why is that? and is there a way around it?
Thanks,
Scott
Hi Raymond
I have no doubt that you are correct, however, I had assumed that Scot was
referring to the time it takes to catch and throw an exception.
I have noticed that the first time an exception is thrown and caught, a .NET
application can take a significant time (several seconds) before returning
control to the catch block.
Unfortunately for Scot, I don't know why this should be, so I am watching
this thread with interest in case there is anything I can do about it as
well. It does not seem to matter whether the exception is thrown manually
either; the first time always takes several seconds.
Charles
"Raymond Lewallen" <Ra************ ******@nospam.f aa.gov> wrote in message
news:Oq******** *****@tk2msftng p13.phx.gbl... Scot,
This is mostly likely due to the time it is taking for your DNS server to
attempt to resolve the DNS name to an IP address. It is not uncommon for
3-6 seconds to pass while DNS attempts to resolve an entry that does not
exist. There is no way around the time it takes for a DNS server to
exhaust its resources in an attempt to resolve hostnames to ip addresses.
HTH,
Raymond Lewallen
"Scot" <bl***@blank.bl ank.com> wrote in message
news:c5******** @library1.airne ws.net... I have the following code:
Dim IP, domainName As String
domainName = "yahoo.com"
Try
IP =
System.Net.Dns. GetHostByName(d omainName).Addr essList(0).ToSt ring() Catch ex As Exception
IP = "Not Valid"
End Try
Console.WriteLi ne(IP)
System.Threadin g.Thread.Sleep( 2000)
When it has a resolvable domain, like yahoo.com it responds back
instantly with the ip address. However, if there is a domain in there that does
not exist, like blue2343.com, it takes upwards of 5 seconds to print "Not
Valid" to the screen. Why is that? and is there a way around it?
Thanks,
Scott
Hi Raymond
I have no doubt that you are correct, however, I had assumed that Scot was
referring to the time it takes to catch and throw an exception.
I have noticed that the first time an exception is thrown and caught, a .NET
application can take a significant time (several seconds) before returning
control to the catch block.
Unfortunately for Scot, I don't know why this should be, so I am watching
this thread with interest in case there is anything I can do about it as
well. It does not seem to matter whether the exception is thrown manually
either; the first time always takes several seconds.
Charles
"Raymond Lewallen" <Ra************ ******@nospam.f aa.gov> wrote in message
news:Oq******** *****@tk2msftng p13.phx.gbl... Scot,
This is mostly likely due to the time it is taking for your DNS server to
attempt to resolve the DNS name to an IP address. It is not uncommon for
3-6 seconds to pass while DNS attempts to resolve an entry that does not
exist. There is no way around the time it takes for a DNS server to
exhaust its resources in an attempt to resolve hostnames to ip addresses.
HTH,
Raymond Lewallen
"Scot" <bl***@blank.bl ank.com> wrote in message
news:c5******** @library1.airne ws.net... I have the following code:
Dim IP, domainName As String
domainName = "yahoo.com"
Try
IP =
System.Net.Dns. GetHostByName(d omainName).Addr essList(0).ToSt ring() Catch ex As Exception
IP = "Not Valid"
End Try
Console.WriteLi ne(IP)
System.Threadin g.Thread.Sleep( 2000)
When it has a resolvable domain, like yahoo.com it responds back
instantly with the ip address. However, if there is a domain in there that does
not exist, like blue2343.com, it takes upwards of 5 seconds to print "Not
Valid" to the screen. Why is that? and is there a way around it?
Thanks,
Scott
Charles, Scot,
Perhaps Scot can step through his code and tell us if the delay is coming
when he steps into the GetHostByName method, or when he steps into the
Catch. Personally, I haven't noticed any delays in .NET code when an
exception is being thrown for the first time. Maybe thats because I'm not
looking for it :)
Raymond Lewallen
"Charles Law" <bl***@nowhere. com> wrote in message
news:el******** ******@tk2msftn gp13.phx.gbl... Hi Raymond
I have no doubt that you are correct, however, I had assumed that Scot was
referring to the time it takes to catch and throw an exception.
I have noticed that the first time an exception is thrown and caught, a
..NET application can take a significant time (several seconds) before returning
control to the catch block.
Unfortunately for Scot, I don't know why this should be, so I am watching
this thread with interest in case there is anything I can do about it as
well. It does not seem to matter whether the exception is thrown manually
either; the first time always takes several seconds.
Charles
"Raymond Lewallen" <Ra************ ******@nospam.f aa.gov> wrote in message
news:Oq******** *****@tk2msftng p13.phx.gbl... Scot,
This is mostly likely due to the time it is taking for your DNS server
to attempt to resolve the DNS name to an IP address. It is not uncommon
for 3-6 seconds to pass while DNS attempts to resolve an entry that does not
exist. There is no way around the time it takes for a DNS server to
exhaust its resources in an attempt to resolve hostnames to ip addresses.
HTH,
Raymond Lewallen
"Scot" <bl***@blank.bl ank.com> wrote in message
news:c5******** @library1.airne ws.net... I have the following code:
Dim IP, domainName As String
domainName = "yahoo.com"
Try
IP =
System.Net.Dns. GetHostByName(d omainName).Addr essList(0).ToSt ring() Catch ex As Exception
IP = "Not Valid"
End Try
Console.WriteLi ne(IP)
System.Threadin g.Thread.Sleep( 2000)
When it has a resolvable domain, like yahoo.com it responds back
instantly with the ip address. However, if there is a domain in there that does not exist, like blue2343.com, it takes upwards of 5 seconds to print "Not
Valid" to the screen. Why is that? and is there a way around it?
Thanks,
Scott
Charles, Scot,
Perhaps Scot can step through his code and tell us if the delay is coming
when he steps into the GetHostByName method, or when he steps into the
Catch. Personally, I haven't noticed any delays in .NET code when an
exception is being thrown for the first time. Maybe thats because I'm not
looking for it :)
Raymond Lewallen
"Charles Law" <bl***@nowhere. com> wrote in message
news:el******** ******@tk2msftn gp13.phx.gbl... Hi Raymond
I have no doubt that you are correct, however, I had assumed that Scot was
referring to the time it takes to catch and throw an exception.
I have noticed that the first time an exception is thrown and caught, a
..NET application can take a significant time (several seconds) before returning
control to the catch block.
Unfortunately for Scot, I don't know why this should be, so I am watching
this thread with interest in case there is anything I can do about it as
well. It does not seem to matter whether the exception is thrown manually
either; the first time always takes several seconds.
Charles
"Raymond Lewallen" <Ra************ ******@nospam.f aa.gov> wrote in message
news:Oq******** *****@tk2msftng p13.phx.gbl... Scot,
This is mostly likely due to the time it is taking for your DNS server
to attempt to resolve the DNS name to an IP address. It is not uncommon
for 3-6 seconds to pass while DNS attempts to resolve an entry that does not
exist. There is no way around the time it takes for a DNS server to
exhaust its resources in an attempt to resolve hostnames to ip addresses.
HTH,
Raymond Lewallen
"Scot" <bl***@blank.bl ank.com> wrote in message
news:c5******** @library1.airne ws.net... I have the following code:
Dim IP, domainName As String
domainName = "yahoo.com"
Try
IP =
System.Net.Dns. GetHostByName(d omainName).Addr essList(0).ToSt ring() Catch ex As Exception
IP = "Not Valid"
End Try
Console.WriteLi ne(IP)
System.Threadin g.Thread.Sleep( 2000)
When it has a resolvable domain, like yahoo.com it responds back
instantly with the ip address. However, if there is a domain in there that does not exist, like blue2343.com, it takes upwards of 5 seconds to print "Not
Valid" to the screen. Why is that? and is there a way around it?
Thanks,
Scott
I think Charles is correct in his assumption. I understand that DNS lookups
on non-existant domains take longer, but not in the 3 to 5 second range. A
second or two would be acceptable, but even that would be long if you there
was minimal network latency.
I believe it is something in the Try..Catch segment. Anyone?
"Raymond Lewallen" <Ra************ ******@nospam.f aa.gov> wrote in message
news:Oq******** *****@tk2msftng p13.phx.gbl... Scot,
This is mostly likely due to the time it is taking for your DNS server to
attempt to resolve the DNS name to an IP address. It is not uncommon for
3-6 seconds to pass while DNS attempts to resolve an entry that does not
exist. There is no way around the time it takes for a DNS server to
exhaust its resources in an attempt to resolve hostnames to ip addresses.
HTH,
Raymond Lewallen
"Scot" <bl***@blank.bl ank.com> wrote in message
news:c5******** @library1.airne ws.net... I have the following code:
Dim IP, domainName As String
domainName = "yahoo.com"
Try
IP =
System.Net.Dns. GetHostByName(d omainName).Addr essList(0).ToSt ring() Catch ex As Exception
IP = "Not Valid"
End Try
Console.WriteLi ne(IP)
System.Threadin g.Thread.Sleep( 2000)
When it has a resolvable domain, like yahoo.com it responds back
instantly with the ip address. However, if there is a domain in there that does
not exist, like blue2343.com, it takes upwards of 5 seconds to print "Not
Valid" to the screen. Why is that? and is there a way around it?
Thanks,
Scott
I think Charles is correct in his assumption. I understand that DNS lookups
on non-existant domains take longer, but not in the 3 to 5 second range. A
second or two would be acceptable, but even that would be long if you there
was minimal network latency.
I believe it is something in the Try..Catch segment. Anyone?
"Raymond Lewallen" <Ra************ ******@nospam.f aa.gov> wrote in message
news:Oq******** *****@tk2msftng p13.phx.gbl... Scot,
This is mostly likely due to the time it is taking for your DNS server to
attempt to resolve the DNS name to an IP address. It is not uncommon for
3-6 seconds to pass while DNS attempts to resolve an entry that does not
exist. There is no way around the time it takes for a DNS server to
exhaust its resources in an attempt to resolve hostnames to ip addresses.
HTH,
Raymond Lewallen
"Scot" <bl***@blank.bl ank.com> wrote in message
news:c5******** @library1.airne ws.net... I have the following code:
Dim IP, domainName As String
domainName = "yahoo.com"
Try
IP =
System.Net.Dns. GetHostByName(d omainName).Addr essList(0).ToSt ring() Catch ex As Exception
IP = "Not Valid"
End Try
Console.WriteLi ne(IP)
System.Threadin g.Thread.Sleep( 2000)
When it has a resolvable domain, like yahoo.com it responds back
instantly with the ip address. However, if there is a domain in there that does
not exist, like blue2343.com, it takes upwards of 5 seconds to print "Not
Valid" to the screen. Why is that? and is there a way around it?
Thanks,
Scott
Scot,
What happens when you step into the code? Does it takes this long everytime
you run the app, even if the process is not recycled? Charles is saying "I
have noticed that the first time an exception is thrown and caught, a .NET
application can take a significant time (several seconds) before returning
control to the catch block." Have you confirmed this is what is happening
by stepping into the try...catch block?
Raymond Lewallen
"Scot" <bl***@blank.bl ank.com> wrote in message
news:c5******** @library1.airne ws.net... I think Charles is correct in his assumption. I understand that DNS
lookups on non-existant domains take longer, but not in the 3 to 5 second range.
A second or two would be acceptable, but even that would be long if you
there was minimal network latency.
I believe it is something in the Try..Catch segment. Anyone?
"Raymond Lewallen" <Ra************ ******@nospam.f aa.gov> wrote in message
news:Oq******** *****@tk2msftng p13.phx.gbl... Scot,
This is mostly likely due to the time it is taking for your DNS server
to attempt to resolve the DNS name to an IP address. It is not uncommon
for 3-6 seconds to pass while DNS attempts to resolve an entry that does not
exist. There is no way around the time it takes for a DNS server to
exhaust its resources in an attempt to resolve hostnames to ip addresses.
HTH,
Raymond Lewallen
"Scot" <bl***@blank.bl ank.com> wrote in message
news:c5******** @library1.airne ws.net... I have the following code:
Dim IP, domainName As String
domainName = "yahoo.com"
Try
IP =
System.Net.Dns. GetHostByName(d omainName).Addr essList(0).ToSt ring() Catch ex As Exception
IP = "Not Valid"
End Try
Console.WriteLi ne(IP)
System.Threadin g.Thread.Sleep( 2000)
When it has a resolvable domain, like yahoo.com it responds back
instantly with the ip address. However, if there is a domain in there that does not exist, like blue2343.com, it takes upwards of 5 seconds to print "Not
Valid" to the screen. Why is that? and is there a way around it?
Thanks,
Scott
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