strip carriage return & append next line

Hello everyone,
I am trying to search a file for lines that start with 'ip:' and have a carriage return after(ip:$). I then want to remove the carriage return from that line and append the next line in the file to the line containing 'ip'. I tried doing this with SED, but had no luck. Any assistance would be greatly appreciated.

COMMAND I TRIED(didnt work):
> sed 's/ip$/ip/g' <file_name>

## ORIGINAL FILE

I want to make the file look like file below:

awk -F":" '/ip/ && $2==""{ getline l;print $0,l; next}1' file

awk '/^ip:$/ { printf "%s ", $0; next } { print }'

awk '/^ip: *$/ { printf "%s ", $0; next } { print }' file