CODEWITHSUNDEEP
linuxbashterminal
user1944429
user1944429

Reputation:

Linux send URL my IP address on startup

So, I'm trying to write a simple bash script to send my internal IP address to a website of mine on startup. I am on a network with DHCP, so I don't always know what the IP address of my Raspberry Pi will be after I do a reboot over ssh. I figured I could fix this by sending my website the current IP on startup. I haven't written many bash scripts, and I'm not really sure how to send data to my website. Right now I was just trying in the terminal this:

wget -qO- http://http://mywebsite.com/private/CurrentIP.php?send=$(/sbin/ifconfig eth0|grep 'inet addr:')

But I'm not having any luck. I don't actually know much about linux, and I'm trying to learn. That's why I got the raspberry pi actually. Anyway, can someone head me in the right direction?

I already know I need to put it in /etc/init.d/.

Upvotes: 0

Views: 1848

Answers (3)

pobrelkey
pobrelkey

Reputation: 5973

You could do this:

IP_ADDR=$(ifconfig eth0 | sed -rn 's/^.*inet addr:(([0-9]+\.){3}[0-9]+).*$/\1/p')
wget -q -O /dev/null http://mywebsite.com/private/CurrentIP.php?send=${IP_ADDR}

...but if your machine is stuck behind NAT, $IP_ADDR won't be your externally-visible address. Might want to use $_SERVER['REMOTE_ADDR'] in your PHP instead of/in addition to this to get the address for your client that your server sees.

Edit: Sounds like you want to be able to find your Raspberry Pi on your local (DHCP-managed) network after reboots. Have you considered using Multicast DNS instead?

How it works in practice: Let's say you've set the hostname of your RasPi to gooseberry. If you've enabled a multicast DNS server on that machine, other computers on the same network segment that can send multicast DNS queries will be able to find it at the domain name gooseberry.local. This is a peer-to-peer protocol and not dependent on gooseberry receiving any specific address via DHCP - so if it reboots and receives a new address, other machines should still be able to find it.

Mac OS X has this enabled out of the box; this can be enabled on most Linux distros (on Debian/Ubuntu you'd install the avahi-daemon and libnss-mdns packages); not sure about Windows, but a quick Google shows encouraging results.

Upvotes: 2

Kyle Banerjee
Kyle Banerjee

Reputation: 2784

Can't you use:

hostname --ip-address

Upvotes: 0

cforbish
cforbish

Reputation: 8819

This worked for me (wget part untested, but it finds IP address):

interface="eth0"
ip_addr=$(ifconfig ${interface} | sed -rn 's/^.*inet *([0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}).*$/\1/p')
wget -q -O /dev/null http://mywebsite.com/private/CurrentIP.php?send=${ip_addr}

Upvotes: 0

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