getting the last IP octet

Projects Programming
1

Ok I've looked everywhere for this and cant find any info.

I have an arduino with an ethernet shield and am using the standard ethernet library, I am trying to populate an integer with the last octet of the IP and just dont know here to start, any help would be greatly appreciated

Cheers

Mike

2

The IPAddress variable can be accessed like an array.

IPAddress ip = Ethernet.localIP();
Serial.println(ip[3]);
3

OMG it was that simple?

I feel like a right tard now :blush:

but thank you :slight_smile:

Mike

4

mikeoxlarge:
OMG it was that simple?

I feel like a right tard now :blush:

Don't feel bad. The documentation doesn't cover stuff like this very well. I know this only by examples and the header/cpp files.

5

I feel like a right tard now

Well, you shouldn't. There was no reason for the Arduino team to borrow a page from Microslop, and obfuscate what used to be quite simple. A mac address or an IP address is a collection of values - an array. There is no reason to use typedefs to give the arrays fancy names that do nothing useful.

6

Hmmmmm, that seems to throw the network adapter in to a fit, sorry guys but am having a really stupid day today, lets say I have the following

int startnum = 0;

How would I get startnum to = the last octet, there's a packet of bourbon biscuits in this for the answer (you pay shipping though) lolol

cheers

Mike

7

What do you meany by "throws the network adapter in a fit"?

IPAddress ip = Ethernet.localIP();
byte startnum = ip[3];

If this doesn't do it, post your code.

8

That did the trick, I'm basically getting three boxes to broadcast every five minutes just the last octet of their ip address, thi is then stored in a table in an application in the pc but also does some other functions in the arduino that needed it as an integer, and it's now working :slight_smile:

Thank you so much :slight_smile:

Am off to the shop now to buy a packet of bourbon cremes :slight_smile: