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8 total

On This Page:

  1. 1 Ping a port with hping3
  2. 2 Analyze internet traffic volume with dynamic ipfw rules
  3. 3 Enable internet traffic via specified ports through ipfw
  4. 4 Enable access to specified web sites through ipfw
  5. 5 Vertical & horizontal split for man screen
  1. 6 ipfwdump, ipfwto & ipfwfrom
  2. 7 Switching firewall settings from the command line
  3. 8 Example ipfw ruleset

Ping a port with hping3

to shell osx mac bash ping unix network web port ipfw internet hping hping3 by jvs on Oct 14, 2008 
# cf. http://trac.macports.org/wiki/InstallingMacPorts
/opt/local/bin/port info hping3
/usr/bin/sudo /opt/local/bin/port install hping3

hping3 --help


# Terminal window 1
alias sudo=/usr/bin/sudo
alias tcpdump=/usr/sbin/tcpdump
#sudo tcpdump -s0 -xX -i lo0 port 4678 and host localhost
sudo tcpdump -s0 -vvv -i lo0 port 4678 and host localhost


# Terminal window 2
alias sudo=/usr/bin/sudo
alias hping3=/opt/local/sbin/hping3
sudo hping3 -I lo0 -s 4678 -c 1 localhost -p 4678
sudo hping3 -S -I lo0 -d 995 -s 4678 -c 1 localhost -p 4678
sudo hping3 -SA -I lo0 -d 995 -w 200 -s 4678 -c 1 localhost -p 4678
sudo hping3 -SA -M 3000 -I lo0 -d 995 -w 65 -s 4678 -c 1 localhost -p 4678
sudo hping3 -DV -SA -I lo0 -s 4678 -a 192.168.1.100 -c 1 localhost -p 4678


#----------------------------------------


# some corresponding ipfw rules for testing purposes 
# (just place them at the beginning of your ipfw rule set)

# not me to me & me to not me
/sbin/ipfw -q add count log all from not me to me 4678 in
/sbin/ipfw -q add count log all from me to not me 4678 out

# any to me & me to any
/sbin/ipfw -q add count log all from any to me 4678 in
/sbin/ipfw -q add count log all from me to any 4678 out
    
# any to any
/sbin/ipfw -q add count log all from any to any 4678

Analyze internet traffic volume with dynamic ipfw rules

to shell osx mac bash unix dynamic web ipfw internet traffic volume rule by jvs on Oct 11, 2008 
# cf. Example ipfw ruleset, http://codesnippets.joyent.com/posts/show/1267
# cf. also http://codesnippets.joyent.com/posts/show/1729

man ipfw 2>/dev/null | less -p "If the ruleset"
man ipfw 2>/dev/null | less -p "These dynamic rules"
man ipfw 2>/dev/null | less -p "All rules"

man ipfw 2>/dev/null | less -p "STATEFUL FIREWALL"     # press [n]
man ipfw 2>/dev/null | less -p "SYSCTL VARIABLES"
man ipfw 2>/dev/null | less -p "EXAMPLES"
man ipfw 2>/dev/null | less -p "DYNAMIC RULES"

/usr/bin/sudo /sbin/ipfw -d -e -t list
/usr/bin/sudo /sbin/ipfw -d -e -t list | /usr/bin/sed -E -n -e '1,/^## Dynamic rules/p'
/usr/bin/sudo /sbin/ipfw -d -e -t list | /usr/bin/sed -E -n -e '/^## Dynamic rules/,$p'
/usr/bin/sudo /sbin/ipfw -d -e -t list | /usr/bin/awk '/^## Dynamic rules/,/^$/ {print $0}'
/usr/bin/sudo /sbin/ipfw -d -e -t list | /usr/bin/awk '/<->/ {print $0}'
/usr/bin/sudo /sbin/ipfw -d -e -t list | /usr/bin/awk '{ if ( $0 ~ /<->/ ) {print $0}}'

/usr/bin/sudo /sbin/ipfw -d -e -t list | grep RULENUM
/usr/bin/sudo /sbin/ipfw -d -e -t list | grep IPADDR

/usr/sbin/sysctl -a | egrep 'tcp'
/usr/sbin/sysctl -a | egrep 'net.inet'
/usr/sbin/sysctl -a | egrep '\.fw'
/usr/sbin/sysctl -a | egrep 'ip.fw'
/usr/sbin/sysctl -a | egrep 'li[fv]e'
/usr/sbin/sysctl -a | egrep 'ip.fw.+life'

/usr/sbin/sysctl -n net.inet.tcp.always_keepalive
/usr/sbin/sysctl -n net.inet.ip.fw.dyn_keepalive
/usr/sbin/sysctl -n net.inet.ip.fw.dyn_buckets
/usr/sbin/sysctl -n net.inet.ip.fw.dyn_count
/usr/sbin/sysctl -n net.inet.ip.fw.dyn_max


# list all dynamic ipfw rules

function ipfwtraffic() {

   declare args argsregex bytes megabytes

   if [[ $# -eq 0 ]]; then

      /usr/bin/sudo /sbin/ipfw -d -e -t list | \
         /usr/bin/awk '/<->/ {printf "%-10s %-10s %-20s %-10s %-20s %-10s %-10s\n", $3, $6, $7, $8, $10, $11, $1}' | \
         /usr/bin/sort -bu | while IFS=" " read  bytes proto ipnum1 port1 ipnum2 port2 rulenum; do

      # byte
      #bytes=$(printf "%s\n" "${bytes}" | /usr/bin/awk '{ total = total + $1 } END { print total }')
      #printf "\e[1mbytes\e[m: %-17s %-10s %-40s \e[1mrule\e[m: %-15s \e[1mports\e[m: %-15s\n" \
           #"${bytes}" "${proto}" "${ipnum1}  ::  ${ipnum2}" "${rulenum}" "${port1}  ${port2}"

      # mega byte
      megabytes=$(printf "%s\n" "${bytes}" | /usr/bin/awk '{ total = (total + $1) / (1024*1024.0) } END { print total }')
      printf "\e[1mmbytes\e[m: %-17s %-10s %-40s \e[1mrule\e[m: %-15s \e[1mports\e[m: %-15s\n" \
           "${megabytes}" "${proto}" "${ipnum1}  ::  ${ipnum2}" "${rulenum}" "${port1}  ${port2}"

      #done | /usr/bin/sort -rn -k 2,2
      done | /usr/bin/sort -rn -k 2,2 | egrep -v '^[^ ]+ +[^ ]+e[^ ]+'

   else

      args="${@}"
      if [[ "${args}" != "${args//[^. [:digit:]]/}" ]]; then 
         printf "%s\n" 'Found at least one invalid rule number or IP address!'
         return 1
      fi

      if [[ "${args//[ [:digit:]]/}" == '' ]]; then 
         argsregex="^0*(${args// /|})"    #  ipfw rule numbers 
      else
         argsregex="(${args// /|})"    #  IP addresses
      fi
    
      #echo $argsregex

      /usr/bin/sudo /sbin/ipfw -d -e -t list | /usr/bin/egrep "${argsregex}" | \
         /usr/bin/awk '/<->/ {printf "%-10s %-10s %-20s %-10s %-20s %-10s %-10s\n", $3, $6, $7, $8, $10, $11, $1}' | \
         /usr/bin/sort -bu | while IFS=" " read  bytes proto ipnum1 port1 ipnum2 port2 rulenum; do

      # byte
      #bytes=$(printf "%s\n" "${bytes}" | /usr/bin/awk '{ total = total + $1 } END { print total }')
      #printf "\e[1mbytes\e[m: %-17s %-10s %-40s \e[1mrule\e[m: %-15s \e[1mports\e[m: %-15s\n" \
           #"${bytes}" "${proto}" "${ipnum1}  ::  ${ipnum2}" "${rulenum}" "${port1}  ${port2}"

      # mega byte
      megabytes=$(printf "%s\n" "${bytes}" | /usr/bin/awk '{ total = (total + $1) / (1024*1024.0) } END { print total }')
      printf "\e[1mmbytes\e[m: %-17s %-10s %-40s \e[1mrule\e[m: %-15s \e[1mports\e[m: %-15s\n" \
           "${megabytes}" "${proto}" "${ipnum1}  ::  ${ipnum2}" "${rulenum}" "${port1}  ${port2}"

      #done | /usr/bin/sort -rn -k 2,2
      done | /usr/bin/sort -rn -k 2,2 | egrep -v '^[^ ]+ +[^ ]+e[^ ]+'

   fi

   return 0
}



# usage:
# ipfwtraffic
# ipfwtraffic [rulenum1] [rulenum2] [rulenum3] ...
# ipfwtraffic [ipaddr1] [ipaddr2] [ipaddr3] ...


ipfwtraffic
ipfwtraffic  9600 10600 11000
ipfwtraffic xx.xxx.xx.xxx xx.xxx.xx.xx

ipfwtraffic | grep 'xx.xxx.xx.xx'



#------------------------------------------------------------------------------



# summarize pairs of IP addresses

function ipfwdynstats() {

   declare args argsregex dynrules ipaddr_pairs

   OIFS=${IFS}
   IFS=$'\n'

   if [[ $# -eq 0 ]]; then

      ipaddr_pairs=($(/usr/bin/sudo /sbin/ipfw -d -e -t list | /usr/bin/awk '/<->/ {print $7, $10}' | /usr/bin/sort -bu))
      dynrules=($(/usr/bin/sudo /sbin/ipfw -d -e -t list | /usr/bin/awk '/<->/ {print $7, $8, $10, $11, $6, $2, $3, $1}' | /usr/bin/sort -bu))

   else

      args="${@}"
      if [[ "${args}" != "${args//[^. [:digit:]]/}" ]]; then 
         printf "%s\n" 'Found at least one invalid rule number or IP address!'
         return 1
      fi

      if [[ "${args//[ [:digit:]]/}" == '' ]]; then 
         argsregex="^0*(${args// /|})"    #  ipfw rule numbers 
      else
         argsregex="(${args// /|})"    #  IP addresses
      fi
    
      #echo $argsregex

      ipaddr_pairs=($(/usr/bin/sudo /sbin/ipfw -d -e -t list | /usr/bin/egrep "${argsregex}" | \
           /usr/bin/awk '/<->/ {print $7, $10}' | /usr/bin/sort -bu))
      dynrules=($(/usr/bin/sudo /sbin/ipfw -d -e -t list | /usr/bin/egrep "${argsregex}" | \
           /usr/bin/awk '/<->/ {print $7, $8, $10, $11, $6, $2, $3, $1}' | /usr/bin/sort -bu))

   fi


for ((i=0; i < "${#ipaddr_pairs[@]}"; i++)); do 

   # byte
   #bytesum=$(printf "%s\n" "${dynrules[@]}" | \
        #/usr/bin/awk "{ if ( \$1 == \"${ipaddr_pairs[${i}]% *}\" && \$3 == \"${ipaddr_pairs[${i}]#* }\" ) print \$7 }" | \
        #/usr/bin/awk '{ total = total + $1 } END { print total }')

   # mega byte
   bytesum=$(printf "%s\n" "${dynrules[@]}" | \
        /usr/bin/awk "{ if ( \$1 == \"${ipaddr_pairs[${i}]% *}\" && \$3 == \"${ipaddr_pairs[${i}]#* }\" ) print \$7 }" | \
        /usr/bin/awk '{ total = (total + $1) / (1024*1024.0) } END { print total }')

   proto=$(printf "%s\n" "${dynrules[@]}" | \
        /usr/bin/awk "{ if ( \$1 == \"${ipaddr_pairs[${i}]% *}\" && \$3 == \"${ipaddr_pairs[${i}]#* }\" ) print \$5 }" | \
        /usr/bin/sort -bu)

   rule=$(printf "%s\n" "${dynrules[@]}" | \
        /usr/bin/awk "{ if ( \$1 == \"${ipaddr_pairs[${i}]% *}\" && \$3 == \"${ipaddr_pairs[${i}]#* }\" ) print \$NF }" | \
        /usr/bin/sort -bu)

   ports=$(printf "%s\n" "${dynrules[@]}" | \
        /usr/bin/awk "{ if ( \$1 == \"${ipaddr_pairs[${i}]% *}\" && \$3 == \"${ipaddr_pairs[${i}]#* }\" ) print \$2, \$4 }" | \
        /usr/bin/sort -bu)

   # byte
   #printf "%-15s %-10s %-40s %-30s \e[1m%-30s\e[m\n" \
        #"bytes: ${bytesum}" "${proto//[[:cntrl:]]/, }" "${ipaddr_pairs[${i}]% *}  ::  ${ipaddr_pairs[${i}]#* }" \
        #"rules: ${rule//[[:cntrl:]]/, }" "ports: ${ports//[[:cntrl:]]/, }"

   # mega byte
   printf "\e[1mmbytes\e[m: %-15s %-10s %-40s \e[1mrules\e[m: %-25s \e[1mports\e[m: %-30s\n" \
        "${bytesum}" "${proto//[[:cntrl:]]/, }" "${ipaddr_pairs[${i}]% *}  ::  ${ipaddr_pairs[${i}]#* }" \
        "${rule//[[:cntrl:]]/, }" "${ports//[[:cntrl:]]/, }"

#done | /usr/bin/sort -rn -k 2,2
done | /usr/bin/sort -rn -k 2,2 | /usr/bin/egrep -v '^[^ ]+ +[^ ]+e[^ ]+'

   export IFS=${OIFS}
   return 0
}

# usage:
# ipfwdynstats
# ipfwdynstats [rulenum1] [rulenum2] [rulenum3] ...
# ipfwdynstats [ipaddr1] [ipaddr2] [ipaddr3] ...


ipfwdynstats
ipfwdynstats  5200 12700
ipfwdynstats xx.xxx.xx.xxx xxx.xxx.xx.xxx



#------------------------------------------------------------------------------



# list port-specific internet traffic

function porttraffic() {

   declare args argsregex dynrules ipaddr_pairs

   OIFS=${IFS}
   IFS=$'\n'

   if [[ $# -eq 0 ]]; then
   
      printf "%s\n" 'No port number given!'
      return 1
   
   elif [[ $# -eq 1 ]]; then

      ipaddr_pairs=($(/usr/bin/sudo /sbin/ipfw -d -e -t list | \
         /usr/bin/awk "{ if ( \$0 ~ /<->/ && ( \$8 == "${1}" || \$11 == "${1}" ) ) {print \$7, \$10 }}" | /usr/bin/sort -bu))

      dynrules=($(/usr/bin/sudo /sbin/ipfw -d -e -t list | \
         /usr/bin/awk "{ if ( \$0 ~ /<->/ && ( \$8 == "${1}" || \$11 == "${1}" ) ) {print \$7, \$8, \$10, \$11, \$6, \$2, \$3, \$1} }" | \
         /usr/bin/sort -bu))

   else

      args="${@:2}"   # all arguments starting with the second
      if [[ "${args}" != "${args//[^. [:digit:]]/}" ]]; then 
         printf "%s\n" 'Found at least one invalid rule number or IP address!'
         return 1
      fi

      if [[ "${args//[ [:digit:]]/}" == '' ]]; then 
         argsregex="^0*(${args// /|})"    #  ipfw rule numbers 
      else
         argsregex="(${args// /|})"    #  IP addresses
      fi
    
      #echo $argsregex

      ipaddr_pairs=($(/usr/bin/sudo /sbin/ipfw -d -e -t list | /usr/bin/egrep "${argsregex}" | \
         /usr/bin/awk "{ if ( \$0 ~ /<->/ && ( \$8 == "${1}" || \$11 == "${1}" ) ) {print \$7, \$10 }}" | /usr/bin/sort -bu))


      dynrules=($(/usr/bin/sudo /sbin/ipfw -d -e -t list | /usr/bin/egrep "${argsregex}" | \
         /usr/bin/awk "{ if ( \$0 ~ /<->/ && ( \$8 == "${1}" || \$11 == "${1}" ) ) {print \$7, \$8, \$10, \$11, \$6, \$2, \$3, \$1}}" | \
         /usr/bin/sort -bu))

   fi


for ((i=0; i < "${#ipaddr_pairs[@]}"; i++)); do 

   # byte
   #bytesum=$(printf "%s\n" "${dynrules[@]}" | \
        #/usr/bin/awk "{ if ( \$1 == \"${ipaddr_pairs[${i}]% *}\" && \$3 == \"${ipaddr_pairs[${i}]#* }\" ) print \$7 }" | \
        #/usr/bin/awk '{ total = total + $1 } END { print total }')

   # mega byte
   bytesum=$(printf "%s\n" "${dynrules[@]}" | \
        /usr/bin/awk "{ if ( \$1 == \"${ipaddr_pairs[${i}]% *}\" && \$3 == \"${ipaddr_pairs[${i}]#* }\" ) print \$7 }" | \
        /usr/bin/awk '{ total = (total + $1) / (1024*1024.0) } END { print total }')

   proto=$(printf "%s\n" "${dynrules[@]}" | \
        /usr/bin/awk "{ if ( \$1 == \"${ipaddr_pairs[${i}]% *}\" && \$3 == \"${ipaddr_pairs[${i}]#* }\" ) print \$5 }" | \
        /usr/bin/sort -bu)

   rule=$(printf "%s\n" "${dynrules[@]}" | \
        /usr/bin/awk "{ if ( \$1 == \"${ipaddr_pairs[${i}]% *}\" && \$3 == \"${ipaddr_pairs[${i}]#* }\" ) print \$NF }" | \
        /usr/bin/sort -bu)

   ports=$(printf "%s\n" "${dynrules[@]}" | \
        /usr/bin/awk "{ if ( \$1 == \"${ipaddr_pairs[${i}]% *}\" && \$3 == \"${ipaddr_pairs[${i}]#* }\" ) print \$2, \$4 }" | \
        /usr/bin/sort -bu)

   # byte
   #printf "%-15s %-10s %-40s %-30s \e[1m%-30s\e[m\n" \
        #"bytes: ${bytesum}" "${proto//[[:cntrl:]]/, }" "${ipaddr_pairs[${i}]% *}  ::  ${ipaddr_pairs[${i}]#* }" \
        #"rules: ${rule//[[:cntrl:]]/, }" "ports: ${ports//[[:cntrl:]]/, }"

   # mega byte
   printf "\e[1mmbytes\e[m: %-15s %-10s %-40s \e[1mrules\e[m: %-25s \e[1mports\e[m: %-30s\n" \
        "${bytesum}" "${proto//[[:cntrl:]]/, }" "${ipaddr_pairs[${i}]% *}  ::  ${ipaddr_pairs[${i}]#* }" \
        "${rule//[[:cntrl:]]/, }" "${ports//[[:cntrl:]]/, }"

#done | /usr/bin/sort -rn -k 2,2
done | /usr/bin/sort -rn -k 2,2 | /usr/bin/egrep -v '^[^ ]+ +[^ ]+e[^ ]+'

   export IFS=${OIFS}
   return 0
}


# usage:
# porttraffic [portnum]
# porttraffic [portnum] [rulenum1] [rulenum2] [rulenum3] ...
# porttraffic [portnum] [ipaddr1] [ipaddr2] [ipaddr3] ...


porttraffic 80
porttraffic 80 5200 12700 7100
porttraffic 80 xx.xxx.xx.xxx xxx.xxx.xx.xxx



#------------------------------------------------------------------------------



# list rule-specific internet traffic

function ruletraffic() {

   declare args argsregex dynrules ipaddr_pairs

   OIFS=${IFS}
   IFS=$'\n'

   if [[ $# -eq 0 ]]; then
   
      printf "%s\n" 'No rule number given!'
      return 1
   
   elif [[ $# -eq 1 ]]; then

      ipaddr_pairs=($(/usr/bin/sudo /sbin/ipfw -d -e -t list | \
         /usr/bin/awk "{ if ( \$0 ~ /<->/ && \$1 == "${1}" ) {print \$7, \$10 }}" | /usr/bin/sort -bu))

      dynrules=($(/usr/bin/sudo /sbin/ipfw -d -e -t list | \
         /usr/bin/awk "{ if ( \$0 ~ /<->/ && \$1 == "${1}" ) {print \$7, \$8, \$10, \$11, \$6, \$2, \$3, \$1} }" | \
         /usr/bin/sort -bu))

   else

      args="${@:2}"   # all arguments starting with the second
      if [[ "${args}" != "${args//[^. [:digit:]]/}" ]]; then 
         printf "%s\n" 'Found at least one invalid rule number or IP address!'
         return 1
      fi

      if [[ "${args//[ [:digit:]]/}" == '' ]]; then 
         argsregex="^0*(${args// /|})"    #  ipfw rule numbers 
      else
         argsregex="(${args// /|})"    #  IP addresses
      fi
    
      #echo $argsregex

      ipaddr_pairs=($(/usr/bin/sudo /sbin/ipfw -d -e -t list | /usr/bin/egrep "${argsregex}" | \
         /usr/bin/awk "{ if ( \$0 ~ /<->/ && \$1 == "${1}" ) {print \$7, \$10 }}" | /usr/bin/sort -bu))


      dynrules=($(/usr/bin/sudo /sbin/ipfw -d -e -t list | /usr/bin/egrep "${argsregex}" | \
         /usr/bin/awk "{ if ( \$0 ~ /<->/ && \$1 == "${1}" ) {print \$7, \$8, \$10, \$11, \$6, \$2, \$3, \$1}}" | \
         /usr/bin/sort -bu))

   fi


for ((i=0; i < "${#ipaddr_pairs[@]}"; i++)); do 

   # byte
   #bytesum=$(printf "%s\n" "${dynrules[@]}" | \
        #/usr/bin/awk "{ if ( \$1 == \"${ipaddr_pairs[${i}]% *}\" && \$3 == \"${ipaddr_pairs[${i}]#* }\" ) print \$7 }" | \
        #/usr/bin/awk '{ total = total + $1 } END { print total }')

   # mega byte
   bytesum=$(printf "%s\n" "${dynrules[@]}" | \
        /usr/bin/awk "{ if ( \$1 == \"${ipaddr_pairs[${i}]% *}\" && \$3 == \"${ipaddr_pairs[${i}]#* }\" ) print \$7 }" | \
        /usr/bin/awk '{ total = (total + $1) / (1024*1024.0) } END { print total }')

   proto=$(printf "%s\n" "${dynrules[@]}" | \
        /usr/bin/awk "{ if ( \$1 == \"${ipaddr_pairs[${i}]% *}\" && \$3 == \"${ipaddr_pairs[${i}]#* }\" ) print \$5 }" | \
        /usr/bin/sort -bu)

   rule=$(printf "%s\n" "${dynrules[@]}" | \
        /usr/bin/awk "{ if ( \$1 == \"${ipaddr_pairs[${i}]% *}\" && \$3 == \"${ipaddr_pairs[${i}]#* }\" ) print \$NF }" | \
        /usr/bin/sort -bu)

   ports=$(printf "%s\n" "${dynrules[@]}" | \
        /usr/bin/awk "{ if ( \$1 == \"${ipaddr_pairs[${i}]% *}\" && \$3 == \"${ipaddr_pairs[${i}]#* }\" ) print \$2, \$4 }" | \
        /usr/bin/sort -bu)

   # byte
   #printf "%-15s %-10s %-40s %-30s \e[1m%-30s\e[m\n" \
        #"bytes: ${bytesum}" "${proto//[[:cntrl:]]/, }" "${ipaddr_pairs[${i}]% *}  ::  ${ipaddr_pairs[${i}]#* }" \
        #"rules: ${rule//[[:cntrl:]]/, }" "ports: ${ports//[[:cntrl:]]/, }"

   # mega byte
   printf "\e[1mmbytes\e[m: %-15s %-10s %-40s \e[1mrules\e[m: %-25s \e[1mports\e[m: %-30s\n" \
        "${bytesum}" "${proto//[[:cntrl:]]/, }" "${ipaddr_pairs[${i}]% *}  ::  ${ipaddr_pairs[${i}]#* }" \
        "${rule//[[:cntrl:]]/, }" "${ports//[[:cntrl:]]/, }"

#done | /usr/bin/sort -rn -k 2,2
done | /usr/bin/sort -rn -k 2,2 | /usr/bin/egrep -v '^[^ ]+ +[^ ]+e[^ ]+'

   export IFS=${OIFS}
   return 0
}


# usage:
# ruletraffic [rulenum]
# ruletraffic [rulenum1] [rulenum2] [rulenum3] ...

ruletraffic 5200
ruletraffic 5200 12700 7100

Enable internet traffic via specified ports through ipfw

to shell osx mac bash unix web port ipfw firewall internet access traffic by jvs on Oct 08, 2008 
# cf. Example ipfw ruleset, http://codesnippets.joyent.com/posts/show/1267

# choose appropriate numbers for num1 & num2 according to your ipfw ruleset

/usr/bin/sudo /sbin/ipfw list
/usr/sbin/sysctl -n net.inet.ip.fw.autoinc_step

function free_ipfw_rule_num() {
   declare -i num1=6701 num2=6799 lastipfwnum
   if [[ $(/usr/sbin/sysctl -n net.inet.ip.fw.autoinc_step) -ne 100 ]]; then 
      printf "%s\x21\n" "sysctl -n net.inet.ip.fw.autoinc_step is not set to 100"
      return 1
   fi
   lastipfwnum=$(/usr/bin/sudo /sbin/ipfw list | /usr/bin/tail -n 2 | /usr/bin/head -n 1 | /usr/bin/awk '{print $1}')
   if [[ $num2 -ge $lastipfwnum ]]; then 
      printf "%s\x21\n" "${num2} is greater than or equal to ${lastipfwnum}"
      return 1
   fi
   while $(/usr/bin/sudo /sbin/ipfw show ${num1} &>/dev/null) ; do
      let "num1 += 1"
      if [[ $num1 -gt $num2 ]]; then num1=; break; return 1; fi
   done
   printf "%s\n" "${num1}"
   return 0
}


function openport() {
   declare portnum rulenum
   if [[ $# -ne 1 ]]; then printf "%s\n" "Wrong number of arguments: $#"; return 1; fi
   portnum="${1//[^[:digit:]]/}"
   if [[ -z $portnum ]]; then printf "%s\n" "No valid port number given: ${1}"; return 1; fi
   if [[ $portnum -gt 65535 ]]; then printf "%s\n" "Given port number is greater than 65535: ${portnum}"; return 1; fi
   rulenum=$(free_ipfw_rule_num)
   /usr/bin/sudo /sbin/ipfw -q add ${rulenum} allow all from any to any dst-port ${portnum} keep-state
   printf "%s\n" "... opening ipfw rule no. ${rulenum} for internet access via port ${portnum}"
   return 0
}


function closeport() {
   declare portnum rulenum
   if [[ $# -ne 1 ]]; then printf "%s\n" "Wrong number of arguments: $#"; return 1; fi
   portnum="${1//[^[:digit:]]/}"
   if [[ -z $portnum ]]; then printf "%s\n" "No valid port number given: ${1}"; return 1; fi
   if [[ $portnum -gt 65535 ]]; then printf "%s\n" "Given port number is greater than 65535: ${portnum}"; return 1; fi
   rulenum=$(/usr/bin/sudo /sbin/ipfw list | /usr/bin/awk "/from +any +to +any +dst-port +${portnum} +keep-state[[:space:]]*$/ {print \$1}")
   if [[ -z "${rulenum}" ]]; then printf "%s\n" "No ipfw rule for port number: ${portnum}"; return 1; fi
   /usr/bin/sudo /sbin/ipfw -q delete ${rulenum}
   printf "%s\n%s\n" "... deleting ipfw rule no. ${rulenum//[[:cntrl:]]/ }" "... closing internet access via port: ${portnum}"
   return 0
}


openport 43
openport 43
openport 43

/usr/bin/sudo /sbin/ipfw show [rulenum]     # ... allow ip from any to any dst-port 43 keep-state

closeport 43

Enable access to specified web sites through ipfw

to shell osx mac bash unix web ipfw firewall internet access traffic website pipestatus by jvs on Oct 07, 2008 
# cf. Example ipfw ruleset, http://codesnippets.joyent.com/posts/show/1267

# choose appropriate numbers for num1 & num2 according to your ipfw ruleset

/usr/bin/sudo /sbin/ipfw list
/usr/sbin/sysctl -n net.inet.ip.fw.autoinc_step

function free_ipfw_rule_num() {
   declare -i num1=6701 num2=6799 lastipfwnum
   if [[ $(/usr/sbin/sysctl -n net.inet.ip.fw.autoinc_step) -ne 100 ]]; then 
      printf "%s\x21\n" "sysctl -n net.inet.ip.fw.autoinc_step is not set to 100"
      return 1
   fi
   lastipfwnum=$(/usr/bin/sudo /sbin/ipfw list | /usr/bin/tail -n 2 | /usr/bin/head -n 1 | /usr/bin/awk '{print $1}')
   if [[ $num2 -ge $lastipfwnum ]]; then 
      printf "%s\x21\n" "${num2} is greater than or equal to ${lastipfwnum}"
      return 1
   fi
   while $(/usr/bin/sudo /sbin/ipfw show ${num1} &>/dev/null) ; do
      let "num1 += 1"
      if [[ $num1 -gt $num2 ]]; then num1=; break; return 1; fi
   done
   printf "%s\n" "${num1}"
   return 0
}


function opensite() {
   declare ipnum ipfwnum
   if [[ $# -eq 0 ]] || [[ $# -gt 2 ]]; then printf "%s\n" "Wrong number of arguments: $#"; return 1; fi
   ipnum=$(/usr/bin/dig +short ${1} 2>/dev/null | /usr/bin/tail -n 1; exit ${PIPESTATUS[0]})
   if [[ $? -ne 0 ]] || [[ -z "${ipnum}" ]]; then 
      printf "%s\n%s\n" "Are you connected to the internet?" "man dig could not find the IP address of: ${1}"
      return 1
   fi
   ipfwnum=$(free_ipfw_rule_num)
   if [[ $# -eq 1 ]]; then
      /usr/bin/sudo /sbin/ipfw -q add ${ipfwnum} allow { src-ip "${ipnum}" or dst-ip "${ipnum}" } keep-state
      printf "%s\n" "... opening ipfw rule no. ${ipfwnum} for internet access to site: ${1}"
   elif [[ $# -eq 2 ]]; then
      /usr/bin/sudo /sbin/ipfw -q add ${ipfwnum} allow { src-ip "${ipnum}" or dst-ip "${ipnum}" } dst-port "${2//[^[:digit:]]/}" keep-state
      printf "%s\n" "... opening ipfw rule no. ${ipfwnum} for internet access to site: ${1} on port ${2}"
   fi
   return 0
}


function closesite() {
   declare ipnum rulenum
   if [[ "${1//localhost/}" == '' ]]; then printf "%s\n" 'Argument "localhost" is not permitted!'; return 1; fi
   ipnum=$(/usr/bin/dig +short "${1}" 2>/dev/null | /usr/bin/tail -n 1; exit ${PIPESTATUS[0]})
   if [[ $? -ne 0 ]] || [[ -z "${ipnum}" ]]; then 
      printf "%s\n%s\n" "Are you connected to the internet?" "man dig could not find the IP address of: ${1}"
      return 1
   fi
   rulenum=$(/usr/bin/sudo /sbin/ipfw list | /usr/bin/awk "/${ipnum}/ {print \$1}")
   if [[ -z "${rulenum}" ]]; then printf "%s\n" "No ipfw rule for: ${1}"; return 1; fi
   /usr/bin/sudo /sbin/ipfw -q delete ${rulenum}
   printf "%s\n%s\n" "... deleting ipfw rule no. ${rulenum//[[:cntrl:]]/ }" "... closing internet access to site: ${1}"
   return 0
}



# usage: 
# opensite [www.website.com] [optional: portnumber]
# closesite [www.website.com]

# example: http://wooledge.org:8000/BashFAQ

host wooledge.org
dig +short wooledge.org

opensite wooledge.org
opensite wooledge.org
opensite wooledge.org
opensite wooledge.org

closesite wooledge.org


opensite wooledge.org 8080
/usr/bin/sudo /sbin/ipfw show [rule no.]
closesite wooledge.org


#--------------------------------------------


man bash | less -p PIPESTATUS
help set | sed -E "s/(pipefail)/$(printf '\e[1m\\1\e[m')/"

set +o pipefail

ls asx 2>&1 | egrep '.'
echo $?

ls asx 2>&1 | egrep '.'
echo ${PIPESTATUS[*]} 

set -o pipefail

ls asx 2>&1 | egrep '.'
echo $?

ls asx 2>&1 | egrep '.'
echo ${PIPESTATUS[*]} 


# remove all non-numeric characters from a string
str="74n237k ab454c e 4 6 6g6fg6d66d"
echo ${#str}
echo ${str}
echo ${str//[^[:digit:]]/}


# yet another way to the check the reachability of a web site
man scutil
scutil --help
scutil -r www.website.com
scutil -r 127.0.0.1 209.85.129.147

Vertical & horizontal split for man screen

to shell osx mac bash unix vertical horizontal ipfw screen split by jvs on Sep 13, 2008
See: Compiling screen from CVS on OSX for vertical split and Terminal Productivity Tips

export PATH=/usr/local/bin:/usr/local/sbin:/usr/local/lib:/usr/local/include:/usr/bin:/bin:/usr/sbin:/sbin
export IFS=$' \t\n'

# compile & install gawk on Mac OS X
# http://www.gnu.org/software/gawk/

cd ~/Desktop
/usr/bin/curl -L -O http://ftp.gnu.org/pub/gnu/gawk/gawk-3.1.6.tar.gz
/usr/bin/tar -xzf gawk-3.1.6.tar.gz
cd gawk-3.1.6
./configure --help
./configure --disable-nls --prefix=/usr/local
/usr/bin/make
/usr/bin/sudo /usr/bin/make install

/usr/local/bin/gawk --version
stat -x /usr/local/bin/gawk


# enable download from cvs.savannah.gnu.org through ipfw firewall
# cf. Example ipfw ruleset, http://codesnippets.joyent.com/posts/show/1267

# get the IP address
host cvs.savannah.gnu.org
dig -x 199.232.41.69 +short

grep cvs /etc/services
zgrep ':2401' /private/var/log/ipfw*


# get a free ipfw rule number
/usr/sbin/sysctl -n net.inet.ip.fw.autoinc_step
/usr/bin/sudo /sbin/ipfw list

# choose appropriate numbers for num1 & num2 according to your ipfw ruleset
function free_ipfw_num() {
   declare -i num1=6701 num2=6799 lastipfwnum
   if [[ $(/usr/sbin/sysctl -n net.inet.ip.fw.autoinc_step) -ne 100 ]]; then return 1; fi
   lastipfwnum=$(/usr/bin/sudo /sbin/ipfw