Linux telnet shell script - bash

Question

I'm trying to read multiple hosts and ports from a text file (ip.txt) and check if they are connected/failed to connect/timed out, and echo the responses to Telnet_Success.txt/Telnet_Failure.txt/Telnet_Refused.txt files
I have tried the following script, it simply shows all the connection results as failed, but when checking manually one by one, I find some of them connected. any help is appreciated.
Here is the script:
>Telnet_Success.txt
>Telnet_Refused.txt
>Telnet_Failure.txt
file=ip.txt
while read line ; do
ip=$( echo "$line" |cut -d ' ' -f1 )
port=$( echo "$line" |cut -d ' ' -f2 )
if telnet -c $ip $port </dev/null 2>&1 | grep -q Escape; then
echo "$ip $port Connected" >> Telnet_Success.txt
elif telnet -c $ip $port </dev/null 2>&1 | grep -q refused; then
echo "$ip $port Refused" >> Telnet_Refused.txt
else
echo "$ip $port Failed" >> Telnet_Failure.txt
fi
done < ${file}

Answer 1

I can't tell you exactly what's failing from the diagnostics you have provided, but it's definitely a problem that you attempt to call telnet multiple times - you could get different outcomes each time, producing bugs which are hard to troubleshoot. You also have some stylistic issues in your code.
Try this refactoring; see the inline comments.
>Telnet_Success.txt
>Telnet_Refused.txt
>Telnet_Failure.txt
# Why use a variable for something you only reference once anyway?
file=ip.txt
# Use the shell's field splitting facility
# Cope with missing final newline; see
# https://mywiki.wooledge.org/BashFAQ/001#My_text_files_are_broken.21__They_lack_their_final_newlines.21
while read -r ip port _ || [[ -n $port ]]; do
# Run telnet once, capture result for analysis
output=$(telnet -c "$ip" "$port" </dev/null 2>&1)
case $output in
*Escape*)
echo "$ip $port Connected" >> Telnet_Success.txt;;
*refused*)
echo "$ip $port Refused" >> Telnet_Refused.txt;;
*)
echo "$ip $port Failed" >> Telnet_Failure.txt;;
esac
# Always double quote file name variables, just in case
done < "${file}"

Answer 2

Hi looks like the telnet command is the culprit
should be "telnet ip port" not "telnet -c ip port"
file=ip.txt
while read line
do
ip=$( echo "$line" |cut -d ' ' -f1 )
port=$( echo "$line" |cut -d ' ' -f2 )
if telnet $ip $port </dev/null 2>&1 | grep -q Escape
then
echo "$ip $port Connected" >> Telnet_Success.txt
elif telnet $ip $port </dev/null 2>&1 | grep -q refused
then
echo "$ip $port Refused" >> Telnet_Refused.txt
else
echo "$ip $port Failed" >> Telnet_Failure.txt
fi
done < ${file}