SSL cert does not work with IP address for SAN

Question

I am trying to create an SSL certificate for a server which will work internally without giving warnings in Chrome. I've created it using SAN with multiple Subject Alt Names of localhost and the IP address. For some reason it works at localhost but it gives an error using the IP address in both curl and Chrome.

$ curl https://192.168.1.50 
curl: (51) Unable to communicate securely with peer: requested domain name does not match the server's certificate.

$ curl https://localhost
<a href="https://localhost:9090/">Moved Permanently</a>.

Checking it on the command-line shows both names under the SAN section, so I'm not sure why this doesn't work:

$ openssl x509 -text -noout -in server.crt 
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number:
            8d:93:a1:be:d1:03:8f:59
    Signature Algorithm: sha256WithRSAEncryption
        Issuer: C=US, ST=California, L=Los Angeles, O=Alt Systems, OU=Internal, CN=Elliott/emailAddress=xxxxxx
        Validity
            Not Before: Nov  5 21:32:19 2019 GMT
            Not After : Mar 19 21:32:19 2021 GMT
        Subject: C=US, ST=CA, L=Los Angeles, O=Alt Systems, OU=Internal/emailAddress=xxxxxx, CN=alt-pix-la
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (2048 bit)
                Modulus:
                    00:b0:53:b6:0b:f0:94:c1:a8:26:93:79:5a:45:86:
                    36:ac:60:c2:40:a2:bf:25:69:90:9f:8b:b9:3f:63:
                    30:ae:48:cc:f9:f0:9d:d4:15:3d:1c:20:bc:29:6f:
                    57:8f:7d:e9:a5:db:2b:2c:ac:1a:6f:6d:b9:17:98:
                    0e:a0:17:1f:3e:28:4e:42:bd:af:2e:54:dd:ec:ff:
                    7b:00:a5:ed:59:97:8a:6f:95:04:c9:eb:3a:6c:ec:
                    9e:c9:7e:12:ee:ce:cc:be:b7:c1:d3:fe:f6:cf:1d:
                    0d:68:07:68:52:7a:30:5f:f1:29:36:64:b2:a5:e8:
                    5e:a7:f9:75:ab:4b:aa:4b:12:aa:44:59:a3:df:18:
                    45:81:52:b1:4d:00:a4:f2:eb:7e:0d:3e:05:f9:94:
                    1a:aa:e4:2e:9a:ee:0c:59:91:b9:63:f3:5d:98:3b:
                    32:4e:f7:1b:47:e5:a7:54:5c:ba:75:9b:88:09:07:
                    cc:93:06:c3:8a:76:78:83:98:69:1a:8b:e2:fd:cf:
                    70:51:35:09:ba:67:ca:c1:81:f4:65:72:0a:15:7a:
                    12:2d:bc:65:04:7f:b8:c3:22:2b:79:8d:9a:62:54:
                    d2:89:3f:4a:02:72:36:27:6c:ad:50:4d:96:e5:a1:
                    df:8b:fe:51:0b:67:1b:44:4e:57:fc:bb:d7:1d:77:
                    9f:c3
                Exponent: 65537 (0x10001)
        X509v3 extensions:
            X509v3 Authority Key Identifier: 
                keyid:BC:39:94:F0:DC:DF:5D:8E:12:E1:DA:5F:8F:7C:C8:02:B4:0E:19:19

            X509v3 Basic Constraints: 
                CA:FALSE
            X509v3 Key Usage: 
                Digital Signature, Non Repudiation, Key Encipherment, Data Encipherment
            X509v3 Subject Alternative Name: 
                DNS:localhost, DNS:192.168.1.50
    Signature Algorithm: sha256WithRSAEncryption
         54:8e:98:93:53:c2:af:fc:b7:03:5c:6d:d3:7d:9a:d9:2f:99:
         ac:29:dc:0f:02:55:36:9e:70:57:68:df:27:5f:5e:a8:43:05:
         ff:a4:7e:bd:15:99:ff:aa:67:35:93:90:35:e0:e7:20:b4:77:
         7c:bf:6f:29:13:46:fc:56:81:58:60:67:14:ae:a1:1b:44:80:
         92:81:7f:ed:5c:bc:75:36:a9:11:52:9b:28:e1:18:d6:a4:17:
         35:13:6c:bd:be:64:db:70:a5:d4:7f:3e:16:26:73:f9:27:ed:
         7b:03:44:b3:59:2d:53:8d:e2:77:f1:6d:8d:21:c0:d0:2c:96:
         27:0c:c6:4e:6f:63:35:61:3e:b5:62:05:88:76:b5:99:ca:7d:
         64:f9:6b:f4:9b:18:8e:3a:77:82:59:d2:13:c0:14:3c:0a:dc:
         8d:82:38:ca:af:e9:43:06:83:ae:6e:4f:73:29:1d:0a:da:91:
         ea:72:f4:26:f3:59:98:8d:ca:1a:ad:19:17:fd:bb:9f:62:bf:
         85:e0:12:bd:9b:93:26:73:2b:9a:77:ff:c4:34:29:25:fc:c7:
         13:8f:94:b3:28:d7:79:dc:54:57:6c:3d:01:f0:37:5c:a9:28:
         23:13:89:7b:c5:63:51:eb:fc:ad:37:d1:31:cf:f4:2f:8c:9c:
         5f:35:07:79

Answer 1

You're using the wrong SAN type – only actual domain names are allowed in "DNS" type SANs; for IP addresses there is the "iPAddress" type ([7] OCTET STRING).

For OpenSSL you can use:

subjectAltName=IP:192.168.1.50

subjectAltName=IP:2001:db8:1234::4567