According to my last post, you might want to customize some part of information, e.g., order and name. For sorting, you can easily insert sort between the pipe chain.

[root@mail ip]# arp -n | sort -t "." -k 4 -g | ./arptodhcpd.sh 
        host host1 {
                hardware ethernet 00:13:F7:08:20:D2;
                fixed-address 192.168.10.1;
        }
        host host10 {
                hardware ethernet 00:11:2F:44:F9:44;
                fixed-address 192.168.10.10;
        }
        host server2000 {
                hardware ethernet 00:11:85:19:F0:D4;
                fixed-address 192.168.10.42;
        }

However, name and IP address cannot be modified at all. You could do it by redirecting result of arp -n to a file and then modified it first.

[root@mail ip]# arp -n > iplist.txt
[root@mail ip]# cat iplist.txt | ./arptodhcpd.sh

For shorter and more readability, I wrote another script to collect IP address, MAC address and its netbios name in tab separated value (TSV) format. It "s named as collectip.sh.

#!/bin/sh
 
arp -n | awk "
/..:..:..:..:..:../ {
  name="";
  tmp="/tmp/ip2nb.tmp";
  system(sprintf("./ip2nb.sh %s > %s",$1,tmp));
  getline name < tmp
  close(tmp);
  if (name == "") {
    split($1,ip,".");
    name=sprintf("host%s",ip[4]);
  }
  printf("%s\t%s\t%s\n",$1,$3,name);
}
" | sort -k 4 -t "." -g
rm -f /tmp/ip2nb.tmp

As a result, we will get something like below.

[root@mail ip]# ./collectip.sh > iplist.txt
[root@mail ip]# cat iplist.txt
192.168.10.1    00:13:F7:08:20:D2       host1
192.168.10.42   00:11:85:19:F0:D4       server2000

Now we can customize order, IP address, MAC addres, and hostname in iplist.txt and then convert it to dhcpd.conf later using listtodhcpd.sh as follow.

#!/bin/sh
awk "
/..:..:..:..:..:../ {
  printf("\thost %s {\n",$3);
  printf("\t\thardware ethernet %s;\n",$2);
  printf("\t\tfixed-address %s;\n\t}\n",$1);
}"

Below is the result generated by this script.

[root@mail ip]# cat iplist.txt | ./listtodhcpd.sh 
        host host1 {
                hardware ethernet 00:13:F7:08:20:D2;
                fixed-address 192.168.10.1;
        }
        host server2000 {
                hardware ethernet 00:11:85:19:F0:D4;
                fixed-address 192.168.10.42;
        }