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dialt0ne/get_aws_dns_ip.sh

Created December 17, 2015 22:44
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Get AmazonProvidedDNS IP address from the EC2 meta-data
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get_aws_dns_ip.sh
MAC_ADDR=`curl -s http://169.254.169.254/latest/meta-data/mac`
CIDR_FULL=`curl -s http://169.254.169.254/latest/meta-data/network/interfaces/macs/${MAC_ADDR}/vpc-ipv4-cidr-block`
CIDR_BASE=`echo ${CIDR_FULL} | cut -d/ -f1 | cut -d\. -f1-3`
LAST_OCTET=`echo ${CIDR_FULL} | cut -d/ -f1 | cut -d\. -f4`
DNS_OCTET=`expr ${LAST_OCTET} + 2`
DNS_IP="${CIDR_BASE}.${DNS_OCTET}"
echo $DNS_IP
@smougenot
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dns server generic ip is 169.254.169.253 (a.k.a no need to compute the ip with range +2)

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