diff --git a/cmds/exp/tcpdump/gen.go b/cmds/exp/tcpdump/gen.go
new file mode 100644
index 0000000000..be79d8b726
--- /dev/null
+++ b/cmds/exp/tcpdump/gen.go
@@ -0,0 +1,63 @@
+// Copyright 2024 the u-root Authors. All rights reserved
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build ignore
+
+package main
+
+import (
+	"log"
+	"os"
+	"os/exec"
+	"regexp"
+	"strings"
+)
+
+func main() {
+	data, err := os.ReadFile("/etc/services")
+	if err != nil {
+		log.Fatalf("Error opening /etc/services: %v", err)
+	}
+
+	re := regexp.MustCompile(`^(\S+)\s+(\d+)/\S+`)
+
+	ports := make(map[string]string)
+
+	for _, line := range strings.Split(string(data), "\n") {
+		if strings.HasPrefix(line, "#") || len(strings.TrimSpace(line)) == 0 {
+			continue
+		}
+		matches := re.FindStringSubmatch(line)
+		if len(matches) == 3 {
+			service := matches[1]
+			port := matches[2]
+			ports[port] = service
+		}
+	}
+
+	// Generate the content for the Go file
+	content := `// Copyright 2024 the u-root Authors. All rights reserved
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+var wellKnownPortsMap = map[string]string{
+`
+
+	// Append the ports to the content
+	for port, service := range ports {
+		content += `"` + port + `":"` + service + `",` + "\n"
+	}
+	content += "}"
+
+	// Write the content to the Go file
+	if err := os.WriteFile("well_known_ports.go", []byte(content), 0644); err != nil {
+		log.Fatalf("Error writing file: %v", err)
+	}
+
+	if err := exec.Command("gofmt", "-w", "well_known_ports.go").Run(); err != nil {
+		log.Fatalf("Error running gofmt: %v", err)
+	}
+}
diff --git a/cmds/exp/tcpdump/util.go b/cmds/exp/tcpdump/util.go
index ecd61294ae..bd80f360b7 100644
--- a/cmds/exp/tcpdump/util.go
+++ b/cmds/exp/tcpdump/util.go
@@ -11,27 +11,7 @@ import (
 	"github.com/vishvananda/netlink"
 )
 
-var wellKnownPortsMap = map[string]string{
-	"20":  "ftp-data",
-	"21":  "ftp",
-	"22":  "ssh-scp",
-	"23":  "telnet",
-	"25":  "smtp",
-	"53":  "domain",
-	"80":  "http",
-	"88":  "kerberos",
-	"110": "pop3",
-	"119": "nntp",
-	"123": "ntp",
-	"143": "imap",
-	"443": "https",
-	"465": "smtps",
-	"563": "nntps",
-	"989": "ftps-data",
-	"990": "ftps",
-	"993": "imaps",
-	"995": "pop3s",
-}
+//go:generate go run gen.go
 
 // wellKnownPorts returns the well-known name of the port or the port number itself.
 func (cmd cmd) wellKnownPorts(port string) string {
diff --git a/cmds/exp/tcpdump/util_test.go b/cmds/exp/tcpdump/util_test.go
index 906e760881..7d37b839be 100644
--- a/cmds/exp/tcpdump/util_test.go
+++ b/cmds/exp/tcpdump/util_test.go
@@ -44,8 +44,8 @@ func TestWellKnownPorts(t *testing.T) {
 		{
 			name:     "Unknown port without numerical",
 			cmd:      cmd{Opts: flags{Numerical: false}},
-			port:     "8080",
-			expected: "8080",
+			port:     "666",
+			expected: "666",
 		},
 	}
 
diff --git a/cmds/exp/tcpdump/well_known_ports.go b/cmds/exp/tcpdump/well_known_ports.go
new file mode 100644
index 0000000000..e8c18f3d34
--- /dev/null
+++ b/cmds/exp/tcpdump/well_known_ports.go
@@ -0,0 +1,272 @@
+// Copyright 2024 the u-root Authors. All rights reserved
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+var wellKnownPortsMap = map[string]string{
+	"7008":  "afs3-update",
+	"538":   "gdomap",
+	"3306":  "mysql",
+	"1094":  "rootd",
+	"3260":  "iscsi-target",
+	"4500":  "ipsec-nat-t",
+	"4":     "echo",
+	"30865": "csync2",
+	"137":   "netbios-ns",
+	"487":   "saft",
+	"8080":  "http-alt",
+	"2605":  "bgpd",
+	"5353":  "mdns",
+	"7002":  "afs3-prserver",
+	"10081": "kamanda",
+	"445":   "microsoft-ds",
+	"554":   "rtsp",
+	"2602":  "ripd",
+	"199":   "smux",
+	"3632":  "distcc",
+	"1127":  "supfiledbg",
+	"1210":  "predict",
+	"515":   "printer",
+	"2086":  "gnunet",
+	"1812":  "radius",
+	"777":   "moira-update",
+	"88":    "kerberos",
+	"111":   "sunrpc",
+	"17004": "sgi-cad",
+	"1645":  "datametrics",
+	"7001":  "afs3-callback",
+	"6347":  "gnutella-rtr",
+	"7000":  "afs3-fileserver",
+	"1314":  "xtelw",
+	"4559":  "hylafax",
+	"371":   "clearcase",
+	"992":   "telnets",
+	"3690":  "svn",
+	"751":   "kerberos-master",
+	"443":   "https",
+	"3493":  "nut",
+	"607":   "nqs",
+	"6":     "zip",
+	"370":   "codaauth2",
+	"444":   "snpp",
+	"2049":  "nfs",
+	"6002":  "x11-2",
+	"17003": "sgi-gcd",
+	"2583":  "mon",
+	"6001":  "x11-1",
+	"7003":  "afs3-vlserver",
+	"5680":  "canna",
+	"6003":  "x11-3",
+	"7007":  "afs3-bos",
+	"871":   "supfilesrv",
+	"2601":  "zebra",
+	"8081":  "tproxy",
+	"27374": "asp",
+	"4353":  "f5-iquery",
+	"4460":  "ntske",
+	"17002": "sgi-crsd",
+	"11":    "systat",
+	"10809": "nbd",
+	"6004":  "x11-4",
+	"10050": "zabbix-agent",
+	"2431":  "venus-se",
+	"4691":  "mtn",
+	"6667":  "ircd",
+	"6006":  "x11-6",
+	"6445":  "sge-execd",
+	"2628":  "dict",
+	"990":   "ftps",
+	"2401":  "cvspserver",
+	"8088":  "omniorb",
+	"2119":  "gsigatekeeper",
+	"752":   "passwd-server",
+	"655":   "tinc",
+	"5672":  "amqp",
+	"389":   "ldap",
+	"631":   "ipp",
+	"2603":  "ripngd",
+	"5667":  "nsca",
+	"37":    "time",
+	"80":    "http",
+	"427":   "svrloc",
+	"13":    "daytime",
+	"22":    "ssh",
+	"17001": "sgi-cmsd",
+	"60177": "tfido",
+	"4569":  "iax",
+	"6007":  "x11-7",
+	"517":   "talk",
+	"2000":  "cisco-sccp",
+	"2433":  "codasrv-se",
+	"4094":  "sysrqd",
+	"21":    "fsp",
+	"23":    "telnet",
+	"7009":  "afs3-rmtsys",
+	"162":   "snmp-trap",
+	"993":   "imaps",
+	"2432":  "codasrv",
+	"5269":  "xmpp-server",
+	"3130":  "icpv2",
+	"5060":  "sip",
+	"543":   "klogin",
+	"1524":  "ingreslock",
+	"53":    "domain",
+	"5666":  "nrpe",
+	"2608":  "isisd",
+	"10082": "amandaidx",
+	"5222":  "xmpp-client",
+	"6444":  "sge-qmaster",
+	"1649":  "kermit",
+	"7004":  "afs3-kaserver",
+	"19":    "chargen",
+	"164":   "cmip-agent",
+	"1813":  "radius-acct",
+	"512":   "biff",
+	"520":   "route",
+	"779":   "moira-ureg",
+	"9":     "discard",
+	"11112": "dicom",
+	"2792":  "f5-globalsite",
+	"6446":  "mysql-proxy",
+	"8140":  "puppet",
+	"1236":  "rmtcfg",
+	"43":    "whois",
+	"1099":  "rmiregistry",
+	"587":   "submission",
+	"2103":  "zephyr-clt",
+	"60179": "fido",
+	"163":   "cmip-man",
+	"548":   "afpovertcp",
+	"7005":  "afs3-volser",
+	"9098":  "xinetd",
+	"546":   "dhcpv6-client",
+	"2811":  "gsiftp",
+	"1194":  "openvpn",
+	"6696":  "babel",
+	"22125": "dcap",
+	"1178":  "skkserv",
+	"6514":  "syslog-tls",
+	"119":   "nntp",
+	"345":   "pawserv",
+	"1677":  "groupwise",
+	"2104":  "zephyr-hm",
+	"79":    "finger",
+	"464":   "kpasswd",
+	"989":   "ftps-data",
+	"4369":  "epmd",
+	"5556":  "freeciv",
+	"6346":  "gnutella-svc",
+	"7":     "echo",
+	"67":    "bootps",
+	"754":   "krb-prop",
+	"9102":  "bacula-fd",
+	"9667":  "xmms2",
+	"320":   "ptp-general",
+	"706":   "silc",
+	"873":   "rsync",
+	"2947":  "gpsd",
+	"10080": "amanda",
+	"22273": "wnn6",
+	"15":    "netstat",
+	"174":   "mailq",
+	"783":   "spamd",
+	"2604":  "ospfd",
+	"5555":  "rplay",
+	"623":   "asf-rmcp",
+	"1646":  "sa-msg-port",
+	"1313":  "xtel",
+	"465":   "submissions",
+	"646":   "ldp",
+	"6000":  "x11",
+	"9103":  "bacula-sd",
+	"25":    "smtp",
+	"179":   "bgp",
+	"3689":  "daap",
+	"57000": "dircproxy",
+	"69":    "tftp",
+	"123":   "ntp",
+	"10083": "amidxtape",
+	"4190":  "sieve",
+	"750":   "kerberos4",
+	"2121":  "iprop",
+	"513":   "who",
+	"518":   "ntalk",
+	"2600":  "zebrasrv",
+	"143":   "imap2",
+	"2430":  "venus",
+	"2135":  "gris",
+	"3050":  "gds-db",
+	"4899":  "radmin-port",
+	"775":   "moira-db",
+	"138":   "netbios-dgm",
+	"346":   "zserv",
+	"749":   "kerberos-adm",
+	"4949":  "munin",
+	"70":    "gopher",
+	"139":   "netbios-ssn",
+	"3205":  "isns",
+	"5308":  "cfengine",
+	"22128": "gsidcap",
+	"68":    "bootpc",
+	"563":   "nntps",
+	"10000": "webmin",
+	"1080":  "socks",
+	"11371": "hkp",
+	"540":   "uucp",
+	"17500": "db-lsp",
+	"106":   "poppassd",
+	"8021":  "zope-ftp",
+	"102":   "iso-tsap",
+	"514":   "syslog",
+	"6697":  "ircs-u",
+	"210":   "z3950",
+	"4031":  "suucp",
+	"319":   "ptp-event",
+	"1093":  "proofd",
+	"3389":  "ms-wbt-server",
+	"5671":  "amqps",
+	"6005":  "x11-5",
+	"9418":  "git",
+	"20":    "ftp-data",
+	"213":   "ipx",
+	"544":   "kshell",
+	"6379":  "redis",
+	"9101":  "bacula-dir",
+	"10051": "zabbix-trapper",
+	"2607":  "ospfapi",
+	"24554": "binkp",
+	"1":     "rtmp",
+	"113":   "auth",
+	"49":    "tacacs",
+	"995":   "pop3s",
+	"636":   "ldaps",
+	"1352":  "lotusnote",
+	"9673":  "zope",
+	"135":   "epmap",
+	"547":   "dhcpv6-server",
+	"161":   "snmp",
+	"853":   "domain-s",
+	"1433":  "ms-sql-s",
+	"1701":  "l2f",
+	"5061":  "sip-tls",
+	"6566":  "sane-port",
+	"104":   "acr-nema",
+	"110":   "pop3",
+	"2101":  "rtcm-sc104",
+	"7100":  "font-service",
+	"4557":  "fax",
+	"8990":  "clc-build-daemon",
+	"500":   "isakmp",
+	"628":   "qmqp",
+	"209":   "qmtp",
+	"4373":  "remctl",
+	"2102":  "zephyr-srv",
+	"17":    "qotd",
+	"177":   "xdmcp",
+	"5432":  "postgresql",
+	"2":     "nbp",
+	"2606":  "ospf6d",
+	"369":   "rpc2portmap",
+	"1434":  "ms-sql-m",
+}