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== Display the dhcp lease==

according in [[bugzilla:2641]] you have a script which display in your terminal how many computers are connected their ip, mac adress and their expiration of dhcp leases.

 nano dhcpd.lease
paste the content below then save the file
 chmod +x dhcpd.lease

 #!/bin/sh
 #
 # dhcpactiv.sh
 #
 # v.004
 # - rewritten again to pull data from dhcpd files according to labels instead of position
 #
 # v.003
 # - add code to remove tstp information from dpcpd.leases
 #
 # v.002
 # - rewritten to use awk more for parsing
 # - added "GMT" indicator to Expiration col head
 #
 echo "Source        Host                 MAC Address       IP Address      Expiration (GMT)"
 echo "============= ==================== ================= =============== ================"
 #
 awk ' { out = ""} \
      { $1=="lease"||$1=="client-hostname" ? out=" " $2 : out=out } \
      { $1=="binding"||$1=="hardware" ? out= " " $3: out=out } \
      { $1=="ends"? out=" " $3 " " $4: out=out } \
      { $1=="}"? out="\n": out=out } \
      { printf out," " }' /var/lib/dhcpd/dhcpd.leases \
  | grep active \
  | sed -e s/'[{};" ]'/\ /g  \
  | awk '{ printf "%-13s %-20s %-17s %-15s %-10s %-5s\n", "dhcpd.leases", $6, $5, $1, $2, $3 }'
 
 #
 # Now do the same for /etc/dhcpd.conf
 #
 awk ' { out = ""}
       { $1=="host"||$1=="fixed-address" ? out=" " $2 : out=out } \
       { $1=="hardware" ? out= " " $3: out=out } \
       { $1=="}"? out="\n": out=out } \
       { printf out," " }' /etc/dhcpd.conf \
  | grep : \
  | sed -e  s/'[{};\" ]'/\ /g -e  s/\.`config get DomainName`// \
  | awk  '{ printf "%-13s %-20s %-17s %-15s %-15s \n", "dhcpd.conf", $1, $2, $3, "reservation"}'
 #
 # Finally, grab the current arp table
 #
 arp -a \
  |  sed -e s/\\..*\(/\ / -e s/\)// \
  |  awk '{ printf "%-13s %-20s %-17s %-15s %-15s \n", "arp", $1, $4, $2, "n/a"}'

==customize the lease duration==
You can customize the lease duration for the dhcp server ('''dhcpd''') in SME using these instructions.
The commands below will create custom template fragments for <tt>default-lease-time</tt> and <tt>max-lease-time</tt>, re-generate <tt>/etc/dhcpd.conf</tt>, and restart the '''dhcpd''' service in order to activate your changes.
 mkdir -p /etc/e-smith/templates-custom/etc/dhcpd.conf
 cd  /etc/e-smith/templates-custom/etc/dhcpd.conf
 echo "    default-lease-time  {21*86400};"      > 25LeaseTimeDefault
 echo "    max-lease-time      {21*86400};"      > 25LeaseTimeMax
 expand-template /etc/dhcpd.conf
 sv restart dhcpd

=== Notes ===
*  Replace "21" with the desired number of days.
*  The spaces in front of "default-lease-time" and "max-lease-time" are important!
*  SME default 'default-lease-time' is 1 day (86400 seconds).
*  SME default 'max-lease-time' is 7 days (7*86400 = 604800 seconds).
*  The SME <tt>expand-template</tt> command performs the calculation inside the braces and puts the results into the output file without braces.

== Verify your changes ==
Verify that your changes "stuck" by looking at the actual values in /etc/dhcpd.conf:
 grep lease-time /etc/dhcpd.conf
The above sample, using {21*86400}, produces the following in /etc/dhcpd.conf:
    default-lease-time  1814400;
    max-lease-time      1814400;

== Un-Do these customizations ==
You can un-do these customizations with:
 rm -f /etc/e-smith/templates-custom/etc/dhcpd.conf/25LeaseTimeDefault
 rm -f /etc/e-smith/templates-custom/etc/dhcpd.conf/25LeaseTimeMax
 expand-template /etc/dhcpd.conf
 sv restart dhcpd

[[Category:Howto]]
[[Category:Administration]]

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