Get AWS ENI Info based on private DNS name

get_eni_from_private_dns.sh

aws ec2 describe-network-interfaces \
  --filter Name=private-dns-name,Values=ip-10-32-6-29.us-gov-west-1.compute.internal \
  --query 'NetworkInterfaces[].[Attachment.InstanceOwnerId, AvailabilityZone, Description, PrivateIpAddress, SubnetId, VpcId]'

## Result (nested output)
# [
#     [
#         "amazon-elasticsearch",
#         "us-gov-west-1a",
#         "ES dev",
#         "10.32.6.29",
#         "subnet-xxxxxxxxx",
#         "vpc-xxxxxxxx"
#     ]
# ]


aws ec2 describe-network-interfaces \
  --filter Name=private-dns-name,Values=ip-10-32-6-29.us-gov-west-1.compute.internal \
  | jq -r '.NetworkInterfaces[] | .AvailabilityZone, .Description, .PrivateIpAddress, .SubnetId, .VpcId'

## Result (raw output)
# us-gov-west-1a
# ES dev
# 10.32.6.29
# subnet-xxxxxxxxx
# vpc-xxxxxxxxx


aws ec2 describe-network-interfaces \
  --filter Name=private-dns-name,Values=ip-10-32-6-29.us-gov-west-1.compute.internal \
  | jq -r '.NetworkInterfaces[] | [.AvailabilityZone, .Description, .PrivateIpAddress, .SubnetId, .VpcId]'

## Result (array)
# [
#   "us-gov-west-1a",
#   "ES dev",
#   "10.32.6.29",
#   "subnet-xxxxxxxxx",
#   "vpc-xxxxxxxxx"
# ]

Sometimes 3rd party security scanning tools can put you in a predicament where you need to find info about a host, and you only have a private DNS name to play with.

These AWS CLI commands will return info about an AWS Elastic Network Interface (ENI) in a given AWS account in a given AWS region, based on the private DNS name value that you provide.

In some cases, you may want to leverage this info programmatically so it can be input elsewhere e.g. a CI/CD pipeline or
other tool/target.

These examples show how you can use AWS CLI built-in query syntax, or alternatively, something like jq, to return the info in the format you need.