DNS/DHCP migration one-liners

== DNS/DHCP migration one-liners ==

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Generate a list of DNS reverse lookup pointers
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# this creates something like:
# 5    IN   PTR  host1.my.domain.com.
# 6    IN   PTR  host2.my.domain.com.
# 7    IN   PTR  host3.my.domain.com.

x=5; for host in $(<hosts.txt); do echo -e "$((x+y))\t\tIN\t\tPTR\t\t$host."; echo $((y++)) >> /dev/null; done; y=0

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Generate new A-records from old ones, keeping CNAMEs
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# this creates something like:
# host1    IN    A  192.168.1.5
# host2    IN    A  192.168.1.6
# host3    IN    CNAME host2
# host4    IN    A  192.168.1.7

awk 'BEGIN {count=5} {if ( $4 ~ /192.168/ ) { count++; print $1,"\t",$2,"\t",$3,"\t","192.168.10."count } else print $1,"\t",$2,"\t",$3,"\t",$4;}' dns_A_records.orig

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Generate new DHCP entries from the old ones
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# this will grab whole {blocks} of DHCP entries

for host in $(<hosts.txt); do awk "/$host/,/}/" /etc/dhcpd/vlan130.conf; done >> vlan150.conf