New Network Tools Section
I have been meaning to put together some network tools for a while now, and I finally got around to it. I added a new Network Tools section to the site with eight tools that I find myself needing on a regular basis. They all run in the browser – nothing gets sent to a server, they either do the math locally or call a public API directly.
Here is a quick rundown of what is available and how to use each one.
What Is My IP
Does exactly what it says. Hit the page and it pulls your IPv4 address, IPv6 if your connection supports it, your ISP, ASN, location, and any reverse DNS on your IP. Handy when you are on a VPN or a lab network and need to quickly confirm what you are actually hitting the internet from. You can find it at fryguy.net/tools-what-is-my-ip.
IP and Domain Reputation Lookup
Type in an IP or a domain name and it pulls together a bunch of useful info in one shot – WHOIS, open ports and known CVEs from Shodan, ISP and ASN data, and for domains it will do a full DNS record pull and grab registrar info. There are also quick links out to Shodan, AbuseIPDB, VirusTotal, Censys, and ThreatYeti if you want to dig deeper. Find it at fryguy.net/tools-ip-reputation.
BGP / ASN Lookup
Enter an AS number like AS13335 or an IP prefix like 8.8.8.0/24 and it pulls the data from RIPE Stat – announced prefixes, upstream providers, downstream ASNs, and WHOIS. Useful when you are troubleshooting a routing issue or just trying to figure out who owns a block. The upstream ASNs are clickable so you can quickly pivot to a different AS. Find it at fryguy.net/tools-bgp-asn.
DNS Lookup
Query any DNS record type for any domain – A, AAAA, MX, NS, TXT, CNAME, SOA, PTR, CAA, and SRV. It uses Cloudflare’s DNS-over-HTTPS resolver so you are getting real-world results. Toggle the record types you want or hit ALL to grab everything at once. I use this constantly when troubleshooting email delivery issues to check SPF, DKIM, and DMARC records. Find it at fryguy.net/tools-dns-lookup.
IPv4 Visual Subnet Calculator
Enter a network and prefix length and it gives you the subnet address, netmask, range, usable IPs, and host count. The useful part is the Divide and Join buttons – you can click Divide to split any subnet in half, and keep dividing as deep as you need. Great for quickly figuring out a subnetting scheme without having to do it all by hand. Find it at fryguy.net/tools-subnet-calculator.
IPv6 Subnet Calculator
Same idea as the IPv4 calculator but for IPv6. Enter an address and a prefix length and it gives you the full address, compressed form, network address, first and last address in the range, and total host count. Find it at fryguy.net/tools-ipv6-calculator.
Cisco Type 7 Password Decrypter
Paste in a Cisco IOS Type 7 password string from a config and it decrypts it instantly. Type 7 is just a reversible XOR cipher so it is not really encryption – more of an obfuscation. If you find a string like password 7 0822455D0A16 in a config you can drop that hash in and get the plaintext back. Note that this only works for Type 7 – Type 5 is an MD5 hash and cannot be reversed. Find it at fryguy.net/tools-cisco-type7.
JunOS $9$ Password Decrypter
Same idea but for Juniper. JunOS uses a reversible cipher for its $9$ password format that shows up in device configs. Paste in the full $9$ string and it gives you the plaintext. Note that $1$ (MD5), $6$ (SHA-512), and $8$ (SHA-256) are one-way hashes and cannot be decrypted – only $9$ works here. Find it at fryguy.net/tools-junos-password.
All of the tools are linked from the Network Tools page which you can also reach from the nav bar. If there is something useful you think should be added, let me know in the comments.