interesting network commands

## about network info

curl ifconfig.me
curl ipinfo.io
traceroute <domain_name>

Example:

traceroute to google.com (172.217.168.206), 64 hops max, 52 byte packets

This line indicates the start of the traceroute to google.com. The IP address 172.217.168.206 is the resolved address for google.com. "64 hops max" means it will trace the route up to a maximum of 64 network devices (routers, switches, etc.) along the path. "52 byte packets" refers to the size of the test packets being sent.

Each subsequent line represents a “hop” along the path from your computer to the destination.

Asterisks * * * indicate that a hop did not respond within a certain time frame. This could be due to various reasons, such as firewalls blocking ICMP (the protocol used by traceroute), or packet loss.

— — — — — — — —

Suppose you have an ec2 instance that is installed in a private subnet. now if you want to know how other external services will see it’s public ip then the command you need to run is:

dig +short myip.opendns.com @resolver1.opendns.com

Try this command as well…

curl http://checkip.amazonaws.com

The result might be one of the nat-gateway ip that is mapped with the private subnet.

And if you want to do same from a pod, then you have to install a deplyment.yaml as given below and the exec into it with bash and then run same command.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: curl-test
  labels:
    app: curl-test
spec:
  replicas: 1
  selector:
    matchLabels:
      app: curl-test
  template:
    metadata:
      labels:
        app: curl-test
    spec:
      containers:
      - name: curl-container
        image: curlimages/curl
        command: ["/bin/sh"]
        args: ["-c", "while true; do sleep 30; ech hello; done"]

apt-get -y install dnsutils
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following additional packages will be installed:
  bind9-dnsutils bind9-host bind9-libs krb5-locales libbsd0 libedit2 libgssapi-krb5-2 libicu74 libjson-c5 libk5crypto3 libkeyutils1
  libkrb5-3 libkrb5support0 liblmdb0 libmaxminddb0 libnghttp2-14 libuv1t64 libxml2
Suggested packages:
  krb5-doc krb5-user mmdb-bin
The following NEW packages will be installed:
  bind9-dnsutils bind9-host bind9-libs dnsutils krb5-locales libbsd0 libedit2 libgssapi-krb5-2 libicu74 libjson-c5 libk5crypto3
  libkeyutils1 libkrb5-3 libkrb5support0 liblmdb0 libmaxminddb0 libnghttp2-14 libuv1t64 libxml2
0 upgraded, 19 newly installed, 0 to remove and 0 not upgraded.
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Get:18 http://archive.ubuntu.com/ubuntu noble/main amd64 bind9-dnsutils amd64 1:9.18.24-0ubuntu5 [155 kB]
Get:19 http://archive.ubuntu.com/ubuntu noble/universe amd64 dnsutils all 1:9.18.24-0ubuntu5 [3676 B]
Fetched 14.1 MB in 2s (8917 kB/s)
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root@ubuntu-deployment-79fbbfdc6c-8k7dk:/# dig +short myip.opendns.com @resolver1.opendns.com
3.xxx.***.@@@