diff --git a/LICENSE b/LICENSE
index fef17d1..71ab8af 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,19 +1,51 @@
-Copyright (c) 2020 Adnan Maolood
+go-gemini is available under the terms of the MIT license:
 
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
+	Copyright (c) 2020 Adnan Maolood
 
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
+	Permission is hereby granted, free of charge, to any person obtaining a copy
+	of this software and associated documentation files (the "Software"), to deal
+	in the Software without restriction, including without limitation the rights
+	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+	copies of the Software, and to permit persons to whom the Software is
+	furnished to do so, subject to the following conditions:
 
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
+	The above copyright notice and this permission notice shall be included in all
+	copies or substantial portions of the Software.
+
+	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+	SOFTWARE.
+
+Portions of this program were taken from Go:
+
+	Copyright (c) 2009 The Go Authors. All rights reserved.
+
+	Redistribution and use in source and binary forms, with or without
+	modification, are permitted provided that the following conditions are
+	met:
+
+	   * Redistributions of source code must retain the above copyright
+	notice, this list of conditions and the following disclaimer.
+	   * Redistributions in binary form must reproduce the above
+	copyright notice, this list of conditions and the following disclaimer
+	in the documentation and/or other materials provided with the
+	distribution.
+	   * Neither the name of Google Inc. nor the names of its
+	contributors may be used to endorse or promote products derived from
+	this software without specific prior written permission.
+
+	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+	"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+	LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+	A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+	OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+	SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+	LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+	DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+	THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+	(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+	OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/client.go b/client.go
index d507960..bbdbf24 100644
--- a/client.go
+++ b/client.go
@@ -210,7 +210,8 @@ func (c *Client) Send(req *Request) (*Response, error) {
 				return err
 			}
 			// Check that the certificate is valid for the hostname
-			if err := cert.VerifyHostname(req.Hostname()); err != nil {
+			// Use our own implementation of verifyHostname
+			if err := verifyHostname(cert, req.Hostname()); err != nil {
 				return err
 			}
 			// Check that the client trusts the certificate
diff --git a/verify.go b/verify.go
new file mode 100644
index 0000000..7abef8f
--- /dev/null
+++ b/verify.go
@@ -0,0 +1,227 @@
+package gemini
+
+import (
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/asn1"
+	"net"
+	"strings"
+	"unicode/utf8"
+)
+
+// Hostname verification code from the crypto/x509 package.
+// Modified to allow Common Names in the short term, until new certificates
+// can be issued with SANs.
+
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+var (
+	oidExtensionSubjectAltName = []int{2, 5, 29, 17}
+)
+
+// oidNotInExtensions reports whether an extension with the given oid exists in
+// extensions.
+func oidInExtensions(oid asn1.ObjectIdentifier, extensions []pkix.Extension) bool {
+	for _, e := range extensions {
+		if e.Id.Equal(oid) {
+			return true
+		}
+	}
+	return false
+}
+
+func hasSANExtension(c *x509.Certificate) bool {
+	return oidInExtensions(oidExtensionSubjectAltName, c.Extensions)
+}
+
+// ignoreCN disables interpreting Common Name as a hostname. See issue 24151.
+// NOTE: This is set to false so that certificates with common names will still
+// be supported.
+var ignoreCN = false
+
+func validHostnamePattern(host string) bool { return validHostname(host, true) }
+func validHostnameInput(host string) bool   { return validHostname(host, false) }
+
+// validHostname reports whether host is a valid hostname that can be matched or
+// matched against according to RFC 6125 2.2, with some leniency to accommodate
+// legacy values.
+func validHostname(host string, isPattern bool) bool {
+	if !isPattern {
+		host = strings.TrimSuffix(host, ".")
+	}
+	if len(host) == 0 {
+		return false
+	}
+
+	for i, part := range strings.Split(host, ".") {
+		if part == "" {
+			// Empty label.
+			return false
+		}
+		if isPattern && i == 0 && part == "*" {
+			// Only allow full left-most wildcards, as those are the only ones
+			// we match, and matching literal '*' characters is probably never
+			// the expected behavior.
+			continue
+		}
+		for j, c := range part {
+			if 'a' <= c && c <= 'z' {
+				continue
+			}
+			if '0' <= c && c <= '9' {
+				continue
+			}
+			if 'A' <= c && c <= 'Z' {
+				continue
+			}
+			if c == '-' && j != 0 {
+				continue
+			}
+			if c == '_' {
+				// Not a valid character in hostnames, but commonly
+				// found in deployments outside the WebPKI.
+				continue
+			}
+			return false
+		}
+	}
+
+	return true
+}
+
+// commonNameAsHostname reports whether the Common Name field should be
+// considered the hostname that the certificate is valid for. This is a legacy
+// behavior, disabled by default or if the Subject Alt Name extension is present.
+//
+// It applies the strict validHostname check to the Common Name field, so that
+// certificates without SANs can still be validated against CAs with name
+// constraints if there is no risk the CN would be matched as a hostname.
+// See NameConstraintsWithoutSANs and issue 24151.
+func commonNameAsHostname(c *x509.Certificate) bool {
+	return !ignoreCN && !hasSANExtension(c) && validHostnamePattern(c.Subject.CommonName)
+}
+
+func matchExactly(hostA, hostB string) bool {
+	if hostA == "" || hostA == "." || hostB == "" || hostB == "." {
+		return false
+	}
+	return toLowerCaseASCII(hostA) == toLowerCaseASCII(hostB)
+}
+
+func matchHostnames(pattern, host string) bool {
+	pattern = toLowerCaseASCII(pattern)
+	host = toLowerCaseASCII(strings.TrimSuffix(host, "."))
+
+	if len(pattern) == 0 || len(host) == 0 {
+		return false
+	}
+
+	patternParts := strings.Split(pattern, ".")
+	hostParts := strings.Split(host, ".")
+
+	if len(patternParts) != len(hostParts) {
+		return false
+	}
+
+	for i, patternPart := range patternParts {
+		if i == 0 && patternPart == "*" {
+			continue
+		}
+		if patternPart != hostParts[i] {
+			return false
+		}
+	}
+
+	return true
+}
+
+// toLowerCaseASCII returns a lower-case version of in. See RFC 6125 6.4.1. We use
+// an explicitly ASCII function to avoid any sharp corners resulting from
+// performing Unicode operations on DNS labels.
+func toLowerCaseASCII(in string) string {
+	// If the string is already lower-case then there's nothing to do.
+	isAlreadyLowerCase := true
+	for _, c := range in {
+		if c == utf8.RuneError {
+			// If we get a UTF-8 error then there might be
+			// upper-case ASCII bytes in the invalid sequence.
+			isAlreadyLowerCase = false
+			break
+		}
+		if 'A' <= c && c <= 'Z' {
+			isAlreadyLowerCase = false
+			break
+		}
+	}
+
+	if isAlreadyLowerCase {
+		return in
+	}
+
+	out := []byte(in)
+	for i, c := range out {
+		if 'A' <= c && c <= 'Z' {
+			out[i] += 'a' - 'A'
+		}
+	}
+	return string(out)
+}
+
+// verifyHostname returns nil if c is a valid certificate for the named host.
+// Otherwise it returns an error describing the mismatch.
+//
+// IP addresses can be optionally enclosed in square brackets and are checked
+// against the IPAddresses field. Other names are checked case insensitively
+// against the DNSNames field. If the names are valid hostnames, the certificate
+// fields can have a wildcard as the left-most label.
+//
+// The legacy Common Name field is ignored unless it's a valid hostname, the
+// certificate doesn't have any Subject Alternative Names, and the GODEBUG
+// environment variable is set to "x509ignoreCN=0". Support for Common Name is
+// deprecated will be entirely removed in the future.
+func verifyHostname(c *x509.Certificate, h string) error {
+	// IP addresses may be written in [ ].
+	candidateIP := h
+	if len(h) >= 3 && h[0] == '[' && h[len(h)-1] == ']' {
+		candidateIP = h[1 : len(h)-1]
+	}
+	if ip := net.ParseIP(candidateIP); ip != nil {
+		// We only match IP addresses against IP SANs.
+		// See RFC 6125, Appendix B.2.
+		for _, candidate := range c.IPAddresses {
+			if ip.Equal(candidate) {
+				return nil
+			}
+		}
+		return x509.HostnameError{c, candidateIP}
+	}
+
+	names := c.DNSNames
+	if commonNameAsHostname(c) {
+		names = []string{c.Subject.CommonName}
+	}
+
+	candidateName := toLowerCaseASCII(h) // Save allocations inside the loop.
+	validCandidateName := validHostnameInput(candidateName)
+
+	for _, match := range names {
+		// Ideally, we'd only match valid hostnames according to RFC 6125 like
+		// browsers (more or less) do, but in practice Go is used in a wider
+		// array of contexts and can't even assume DNS resolution. Instead,
+		// always allow perfect matches, and only apply wildcard and trailing
+		// dot processing to valid hostnames.
+		if validCandidateName && validHostnamePattern(match) {
+			if matchHostnames(match, candidateName) {
+				return nil
+			}
+		} else {
+			if matchExactly(match, candidateName) {
+				return nil
+			}
+		}
+	}
+
+	return x509.HostnameError{c, h}
+}