I went through each of these hostnames, pinging them, then doing a WHOIS lookup to determine the Autonomous System (AS) number, which informs which network the host routes to. Ping however will only grab one IP from a list of possible IP Addresses. It turns out that most of these hostnames point to numerous IP addresses. Which makes perfect sense for fault tolerance, geographic dispersion, and redundancy reasons. The next step I listed all IP addresses tied to each seed hostname:
$ dig +short a seed.bitcoin.sipa.be 93.81.254.159 173.241.227.243 5.45.74.50 68.219.242.34 121.226.58.95 136.244.19.126 31.164.160.162 209.204.29.18 51.15.11.99 18.198.16.76 216.82.38.46 92.43.187.34 54.91.248.109 18.217.35.153 31.188.245.244 18.222.149.135 35.205.117.63 37.60.240.209 188.68.53.44 37.60.234.45 73.117.132.138 35.237.144.170 62.24.76.122 109.86.60.33 179.228.234.7
To get a better feel for these IP addresses, I wrote a script to collect various data points on each of these IP addresses. Here is the result of the first hostname:
Hostname IP Address Reverse IP seed.bitcoin.sipa.be 104.62.136.12 104-62-136-12.lightspeed.mssnks.sbcglobal.net seed.bitcoin.sipa.be 134.122.100.130 seed.bitcoin.sipa.be 108.44.152.24 pool-108-44-152-24.clppva.fios.verizon.net seed.bitcoin.sipa.be 86.104.228.41 seed.bitcoin.sipa.be 185.231.220.189 swinglicious.com seed.bitcoin.sipa.be 68.219.242.34 seed.bitcoin.sipa.be 188.166.72.55 seed.bitcoin.sipa.be 65.109.85.139 static.139.85.109.65.clients.your-server.de seed.bitcoin.sipa.be 109.173.126.157 broadband-109-173-126-157.ip.moscow.rt.ru seed.bitcoin.sipa.be 195.56.63.11 seed.bitcoin.sipa.be 167.235.110.208 static.208.110.235.167.clients.your-server.de seed.bitcoin.sipa.be 185.70.43.193 185-70-43-193.protonmail.ch seed.bitcoin.sipa.be 18.162.156.95 ec2-18-162-156-95.ap-east-1.compute.amazonaws.com seed.bitcoin.sipa.be 172.234.95.35 172-234-95-35.ip.linodeusercontent.com seed.bitcoin.sipa.be 69.181.240.40 c-69-181-240-40.hsd1.ca.comcast.net seed.bitcoin.sipa.be 62.54.183.27 seed.bitcoin.sipa.be 195.201.86.117 static.117.86.201.195.clients.your-server.de seed.bitcoin.sipa.be 62.210.88.131 23ce2d6f-677d-476e-883f-9d322bdbbc84.fr-par-1.baremetal.scw.cloud seed.bitcoin.sipa.be 192.95.31.84 ns502652.ip-192-95-31.net seed.bitcoin.sipa.be 5.253.18.218 seed.bitcoin.sipa.be 71.188.127.21 static-71-188-127-21.cmdnnj.fios.verizon.net seed.bitcoin.sipa.be 5.189.144.87 m3087.contabo.host seed.bitcoin.sipa.be 177.170.79.252 177-170-79-252.user.vivozap.com.br seed.bitcoin.sipa.be 13.228.111.109 ec2-13-228-111-109.ap-southeast-1.compute.amazonaws.com seed.bitcoin.sipa.be 185.152.138.74 static17.byfly.gomel.by
Just discovered https://bitnodes.io/ which has accomplished much of the initial goal of my project, which was to map the Bitcoin node network and track its growth over time.