As citizens of the Internet, we are all familiar with IP addresses -- probably more so than our Internet founding fathers had ever intended. These addresses are typically represented in a 4-piece segmented list of numbers separated by dots. Here is an example: "149.173.5.120".

Each segment is called an octet because it contains 8 (count 'em, eight!) bits. The four-octect IP address is part of the IPv4 standard.

Note: There is a newer IPv6 standard (featuring 16 octets) that many newer networks use and which allows for more addresses. This has become necessary because all new consumer products are required by law to connect to the Internet. (I think that each of my daughter's "Polly Pocket" pieces can connect to WiFi.) But in this article I'm ignoring IPv6.

The easy-to-read segmented IP address is actually a 32-bit number, and sometimes it is useful to convert the display value into its numeric form. For example, consider the databases that help you to map an IP address to a geographic location in the world. These databases use a numerical range to map an address to a country or city. (For more on range-based geocoding, see this topic in the PROC GEOCODE documentation.)

Here is a SAS program that converts a character-based, 4-segment IP address into its equivalent numeric value. It uses the SCAN function, a DATA step ARRAY, and a little bit of math to do the work:

```/* Calculate the numerical IP from "segmented" IP address */ /* Example: (from Right to Left) */ /* 1.2.3.4 = 4 + (3 * 256) + (2 * 256 * 256) + (1 * 256 * 256 * 256) */ /* is 4 + 768 + 13,1072 + 16,777,216 = 16,909,060 */ data ip_numbers (keep=ip_address ip_numeric); infile datalines dsd; length ip_address \$ 20 ip_numeric 8; input ip_address; array ip_part {4}; do i = 1 to 4; ip_part{i} = scan(ip_address,i,'.'); end; ip_numeric = ip_part{4} + (ip_part{3} * 256) + (ip_part{2} * 256 * 256) + (ip_part{1} * 256 * 256 * 256); datalines; 115.85.65.148 117.203.114.198 118.96.201.156 119.247.220.11 12.201.116.58 128.2.38.96 128.204.197.27 128.204.207.83 134.102.237.2 141.155.113.98 169.2.124.79 172.16.26.231 172.16.30.229 173.234.211.69 176.63.76.232 178.157.198.132 178.32.145.44 178.32.177.184 178.33.174.213 178.63.199.204 184.82.208.149 188.165.187.71 ; run;```

Here's the output:

### Mapping IP address to a geo location

With this mapping, I can then combine my collection of IP addresses with one of the IP-to-geolocation databases that are available. (SAS provides a macro to help work with MaxMind, which you can learn about in this topic.) Here's a sample result:

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+Chris Hemedinger is the manager of SAS Online Communities. Since 1993, Chris has worked for SAS as an author, a software developer, an R&D manager and a consultant. Inexplicably, Chris is still coasting on the limited fame he earned as an author of SAS For Dummies.  He also hosts the SAS Tech Talk webcasts each year from SAS Global Forum, connecting viewers with smart people from SAS R&D and the impressive work that they do.

1. Neat piece of code! I didn't know about the MaxMind autocall macro. As usual, thanks for the tip!

One observation though... The variable name, ip_number in your output dataset screenshot doesn't match the variable name, ip_numeric in your keep= data set option...

• Chris Hemedinger on

Good catch Michelle! The discrepancy is because I built the DATA step as a standalone example, whereas the second image is from my actual production use of this technique. I create reports on our blogs.sas.com activity, including a graphical map that shows where the comments are coming from.

Chalk another one up for Queensland, AU!

• And another one... to help try skew your results ;-)

2. Chris -- we actually used this as part of a cybersecurity project we did with the Navy back in 2004/2005. We were working with large volumes of network sensor data processed through an event correlation engine. We used DI Studio to administer all of our data management activities and the target data store was SPDS. Our IP addresses came across in IP/Port combinations in the format x.x.x.x:y where x is the IP octet and y is the port. We reported on a number of things including country of origin so the numeric equivalent of the IP was important. Here was the code used for that customer implementation:

```data spdsdata.dest_ip_pair_new;
set spdsdata.dest_ip_port_pair_summary_old;
length dip \$15; label dip="Destination IP";
length dport \$10; label dport="Destination Port";
length dipnum 8; label dipnum="Destination IP Number";
length severity 4.; label severity="Severity";
dip = scan(dip_port,1,":");
dport = scan(dip_port,2,":");
dipnum = 16777216*(input(scan(dip_port,1,".:"),8.)) + 65536*
(input(scan(dip_port,2,".:"),8.)) + 256*(input(scan(dip_port,3,".:"),8.)) +
(input(scan(dip_port,4,".:"),8.));
run;
```

3. Here are complimentary PROC FCMP functions I wrote to convert back and forth between numeric and dotted IP addresses. You can remove the INPUT and PUT functions if you don't mind getting the conversion log messages.

```PROC FCMP;
RETURN( BLSHIFT( INPUT( SCAN( ipaddr, 1, '.'), BEST4.), 24) +
BLSHIFT( INPUT( SCAN( ipaddr, 2, '.'), BEST4.), 16) +
BLSHIFT( INPUT( SCAN(  ipaddr, 3, '.'), BEST4.), 8) +
INPUT( SCAN( ipaddr, 4, '.'), BEST4.) );
ENDSUB;

RETURN( CATX( '.', PUT( BRSHIFT( ipaddr, 24), 3.0),
PUT( BAND( BRSHIFT( ipaddr, 16), 255), 3.0),
PUT( BAND( BRSHIFT( ipaddr, 8), 255), 3.0),
PUT( BAND( ipaddr, 255), 3.0) ) );
ENDSUB;
RUN;
```

4. The initial datastep can easily be simplified as follows.
It demonstrates that you can easily re-read the same line both as a character string and as four distinct number simultaneously as follows:

1. using the @1 you start reading again the same line
2. by use of DLM='.' you define separator between adjacent columns
3. by re-writing your formula you only multiply 3 times i.s.o. 6 times.

```data IP_numbers (keep = IP IPnum); infile datalines dlm='.' missover; input IP \$char20. @1 p1 p2 p3 p4; IPnum = ((p1 * 256 + p2) * 256 + p3) * 256 + p4; datalines; 115.85.65.148 117.203.114.198 118.96.201.156 ... ... ```