I'm having real trouble converting my regular expression into a working sed command on Centos 5.5.

I want to filter the IP address out of a string:

```
"example.org has address 123.45.67.890" -> "123.45.67.890"

```

My regular expression so far is:

```
/([a-zA-Z\. ]+)([0-9\.]+)/

```

And an example of my command using sed is:

```
host example.org | grep 'has address' | sed 's/\([a-zA-Z\\. ]+\)\([0-9\\.]+\)/\2/'

```

But all I get back from that command is the input to sed: "example.org has address 123.45.67.890"

Any ideas?