checkip
checkip
Sometimes I come across an IP address, reviewing logs for example, and I want to know more about this numerical label. Checkip is CLI tool and Go library that provides (security) information on IP addresses. It runs various checks to get the information. Most checks are passive, i.e. not interacting directly with the IP address. Active checks, like ping and tls, are not aggressive.
Quick start
$ go install github.com/jreisinger/checkip@latest
$ checkip 1.1.1.1 91.228.166.47
--- 1.1.1.1 ---
db-ip.com Sydney, Australia
dns name one.one.one.one
iptoasn.com CLOUDFLARENET
is on AWS false
isc.sans.edu attacks: 0, abuse contact: abuse@cloudflare.com
ping 0% packet loss (5/5), avg round-trip 4 ms
tls TLS 1.3, exp. 2026/01/21, cloudflare-dns.com, *.cloudflare-dns.com, one.one.one.one
virustotal.com network: 1.1.1.0/24, SAN: cloudflare-dns.com, *.cloudflare-dns.com, one.one.one.one, 1.0.0.1, 1.1.1.1, 162.159.36.1, 162.159.46.1, 2606:4700:4700::1001, 2606:4700:4700::1111, 2606:4700:4700::64, 2606:4700:4700::6400
malicious prob. 0% (0/12) ✅
--- 91.228.166.47 ---
db-ip.com Petržalka, Slovakia
dns name skh1-webredir01-v.eset.com
iptoasn.com ESET-AS
is on AWS false
isc.sans.edu attacks: 0, abuse contact: domains@eset.sk
ping 0% packet loss (5/5), avg round-trip 5 ms
tls TLS 1.3, exp. 2024/01/02!!, www.eset.com, eset.com
virustotal.com network: 91.228.164.0/22, SAN: www.eset.com, eset.com
malicious prob. 17% (2/12) 🤏
More usage examples
Use detailed JSON output to filter out those checks that consider the IP address to be malicious:
checkip -j 91.228.166.47 | jq '.checks[] | select(.ipAddrIsMalicious == true)'
Check multiple IP addresses coming from STDIN:
dig +short eset.sk | checkip
Continuously generate random IP addresses and check them (hit Ctrl-C to stop):
while true; do ./randip; sleep 2; done | checkip 2> /dev/null
Generate 100 random IP addresses and select Russian or Chinese:
./randip 100 | checkip -p 20 -j 2> /dev/null | \
jq -r '.ipAddr as $ip | .checks[] | select (.description == "db-ip.com" and (.ipAddrInfo.iso_code == "RU" or .ipAddrInfo.iso_code == "CN")) | $ip'
Find out who is trying to SSH into your Linux system:
sudo journalctl --unit ssh --since "1 hour ago" | \
grep 'Bye Bye' | perl -wlne '/from ([\d\.]+)/ && print $1' | sort | uniq | \
checkip 2> /dev/null
Installation
To install the CLI tool
# optional; to install inside a container
docker run --rm -it golang /bin/bash
go install github.com/jreisinger/checkip@latest
or download a release binary (from under “Assets”) for your system and architecture.
Configuration and cache
For some checks to start working you need to sign up on a web site (like https://www.abuseipdb.com) and get an API (or LICENSE) key. Checkip doesn’t report an absent API key as an error; the check is simply not executed and missingCredentials JSON field is set to the name of the API key (like ABUSEIPDB_API_KEY).
Store the keys in $HOME/.checkip.yaml file:
ABUSEIPDB_API_KEY: aaaaaaaabbbbbbbbccccccccddddddddeeeeeeeeffffffff11111111222222223333333344444444
MAXMIND_LICENSE_KEY: abcdef1234567890
SHODAN_API_KEY: aaaabbbbccccddddeeeeffff11112222
URLSCAN_API_KEY: abcd1234-a123-4567-678z-a2b3c4b5d6e7
VIRUSTOTAL_API_KEY: aaaaaaaabbbbbbbbccccccccddddddddeeeeeeeeffffffff1111111122222222
You can also use environment variables with the same names.
Data used by some checks is downloaded (cached) to $HOME/.checkip/ folder. Is gets periodically re-downloaded so it is fresh.
Development
Checkip is easy to extend. If you want to add a new way of checking IP addresses:
- Write a function of type check.Func.
- Add it to check.Funcs variable.
Typical workflow:
make run # test and run
git commit
git tag | sort -V | tail -1
git tag -a v0.2.0 -m "new check func"
git push --follow-tags # will build a new release on GitHub