IPAddress.Parse(aIpAddress) returns a wrong IP Address

[Rainer Queck]

Hello NG,

what is it I am doing wrong?
If I call IPAddress.Parse(aIpAddress) where the string aIpAddress =
"172.017.024.015" I get {172.15.20.13} as a result.

How can that be?

Regards
Rainer

 

[Nicholas Paldino [.NET/C# MVP]]

Rainer,

It's the extra 0's in the last three parts of the address. Remove
those, and it works.

How did they get in there in the first place? I think that it is
screwing up because with the 0's in there at that place, it is trying to
figure out if it is a class A or a class B address.

 

[Nicholas Paldino [.NET/C# MVP]]

Rainer,

Debugging the source code, I see that a call is eventually made to
inet_addr to parse the address. Looking at the documentation, it states
that with the leading 0, it is interpreted as an octal value.

http://msdn2.microsoft.com/en-us/library/ms738563.aspx

And that makes sense, as 017 in octal is 15, 024 is 20, and 015 is 13.

 

[LVP]

Good job Nicholas.

Thanks,

Rainer,

Debugging the source code, I see that a call is eventually made to
inet_addr to parse the address. Looking at the documentation, it states
that with the leading 0, it is interpreted as an octal value.

http://msdn2.microsoft.com/en-us/library/ms738563.aspx

And that makes sense, as 017 in octal is 15, 024 is 20, and 015 is 13.


--
- Nicholas Paldino [.NET/C# MVP]
- (e-mail address removed)

Hello NG,

what is it I am doing wrong?
If I call IPAddress.Parse(aIpAddress) where the string aIpAddress =
"172.017.024.015" I get {172.15.20.13} as a result.

How can that be?

Regards
Rainer

 

[Mihai N.]

Debugging the source code, I see that a call is eventually made to

inet_addr to parse the address. Looking at the documentation, it states
that with the leading 0, it is interpreted as an octal value.

Not only that is makes sense, but it also looks like the correct thing:
http://en.wikipedia.org/wiki/IPv4#Address_representations