Ubuntu/Scripts
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Scripts | SSL Expire
Contents |
Email current IP address
Variables needing to be defined:
- sender domain (@sender domain.com)
- recipient (recipient address)
Variables automatically defined
- HOSTNAME - defined by using the hostname command
- DATE - defined by using the date command
- IP - queries checkip.dyndns.org and then parses the return to exclude everything except the IP address
- UPTIME - defined by using the uptime command
- USERS - defined by using the users command
- RECIP_DOMAIN - defined by parsing the domain from the recipients' address
- RECIP_MX - defined by querying the recipient's MX and picking the record with the highest priority
- SENDER_DOMAIN - defined by parsing the domain from the senders' address, used for the messageid
- MESSAGEID - automatically created using random numbers and the sender's domain
- BOUNDARY - automatically created for content-type boundaries
Code
#!/bin/bash -x
#static variables
from="$HOSTNAME"'@sender domain.com'
to='recipient address'
#dynamic variables
HOSTNAME=$(hostname)
#recipient_mx='recipient mail exchanger' ---obsolete
DATE=$(date -R)
sender_domain=$(printf "$from" | sed 's/^.*@//')
messageidrandom=$(od -vAn -N4 -tu4 < /dev/urandom)
messageidrandom=$(printf "$messageidrandom" | sed 's/ //')
messageid="$messageidrandom"'@'"$sender_domain"
IP=$(curl checkip.dyndns.org|awk '/Address:/ {print$6}'|sed 's/<.*/ /')
UPTIME=$(uptime)
USERS=$(users)
recip_domain=$(printf "$to" | sed 's/^.*@//')
recip_mx=$(dig +short $recip_domain mx | sort -n | nawk '{print $2;exit}' | sed 's/\(.*\)./\1/')
boundaryrandom=$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1)
boundary='b1_'"$boundaryrandom"
#function containing mail commands. Contains enough RFC required fields to satisfy gmail's requirements to allow the message, though it may be detected as spam if you do not have a SPF record.
function mail_input {
sleep 1
printf 'ehlo test.com\n'
sleep 0.5
printf 'mail from:<'"$from"'>\n'
sleep 1
printf 'rcpt to:<'"$to"'>\n'
sleep 1
printf 'data\n'
sleep 0.5
printf 'Return-Path: <'"$from"'>\n'
printf 'Date: '"$DATE"'\n'
printf 'Message-ID: <'"$messageid"'>\n'
printf 'Subject: '"$HOSTNAME"' ip address= '"$IP"'\n'
printf 'From: <'"$from"'>\n'
printf 'To: <'"$to"'>\n'
printf 'Content-type: multipart/alternative;\n'
printf ' boundary="'"$boundary"'"\n'
printf '\n'
printf '\n'
printf "%s\n" '--'"$boundary"''
printf 'Content-type: text/plain;\n'
printf ' charset="UTF-8"\n'
printf 'Content-transfer-encoding: quoted-printable\n'
printf '\n'
printf 'hostname: '"$HOSTNAME"'\n'
printf 'ip address: '"$IP"'\n'
printf 'uptime: '"$UPTIME"'\n'
printf 'users logged in: '"$USERS"'\n'
printf '\n'
printf '\n'
printf "%s\n" '--'"$boundary"''
printf 'Content-type: text/html;\n'
printf ' charset="UTF-8"\n'
printf 'Content-transfer-encoding: quoted-printable\n'
printf '\n'
printf '<html>\n'
printf '<head>\n'
printf '<meta http-equiv=3D"Content-Type" content="3Dtext/html; charset=3Dutf-8">\n'
printf '</head>\n'
printf '<body>\n'
printf 'hostname: '"$HOSTNAME"'<br>\n'
printf 'ip address: '"$IP"'<br>\n'
printf 'uptime: '"$UPTIME"'<br>\n'
printf 'users logged in: '"$USERS"'<br>\n'
printf '</body>\n'
printf '</html>\n'
printf '\n'
printf '\n'
printf "%s\n" '--'"$boundary"'--'
printf '\n'
printf '\n'
printf '\n'
printf '.\n'
sleep 3
printf 'quit'
sleep 10
kill $$
}
#sending mail with mail_input function
#plain text
mail_input | telnet $recip_mx 25
#TLS encrypted
#mail_input | openssl s_client -crlf -starttls smtp -quiet -connect $recip_mx:25
Learned
- you cannot define a variable as the same exact spelling of the command.
WRONG: hostname ≠ `hostname` RIGHT: HOSTNAME = `hostname`
- you can call a standard command and define its output as a variable, so long as you use " ` " around the command (old school) or "$( )" around it
WRONG: HOSTNAME ≠ 'hostname' RIGHT: HOSTNAME = `hostname` RIGHT: HOSTNAME = $(hostname)
- when using printf you should be careful which type of quote to use. a single quote should be used for plain text, such as a static heading to an output. a double quote should be used for defining variables.
WRONG: printf "Address: " '$IP' "\n" RIGHT: printf 'Address: ' "$IP" '\n'
adding -x to your #!/bin/bash statement will cause everything to be printed, useful in troubleshooting
#!/bin/bash -x
- a wise man told me that i'm supposed to separate the headers from the body of the message with (2) linefeeds. Added to the script.
