grep ips from BFD bans, invalid back reference ?

from shell,

bfd -a | grep '\([0-9]{1,3}(\.[0-9]{1,3}){3})\1'

Gives me the error invalid back reference,

bfd -a | grep -P "[0-9]{1,3}(\.[0-9]{1,3}){3}"
prints proftpd proftpd proftpd proftpd proftpd proftpd proftpd proftpd proftpd proftpd

How do I just capture the ip's and loose anything after it ?
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> grep '\([0-9]{1,3}(\.[0-9]{1,3}){3})\1'

-) what are you trying to match ?
-) the number of opening and closing "(" does not match
-) the "-P" argument to grep is missing
ghboomAuthor Commented:
oops my bad,
I pasted the wrong error...
I have been trying many examples from various sources
learning about this, ultimatly I have tried

bfd -a | grep -P "\([0-9]{1,3}(\.[0-9]{1,3}){3}\)\1"

however there is no results returned...

what I am looking for is to, only have the IPs returned, not any txt.

so typing
bfd -a | grep -P "[0-9]{1,3}(\.[0-9]{1,3}){3}" proftpd proftpd

I would like to only have ips retrned like,

bfd -a | grep -P "[0-9]{1,3}(\.[0-9]{1,3}){3}" |awk '{print $1}'

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ghboomAuthor Commented:
great, works like a charm !!

Thanks ;)
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