Generate certificates on RouterOS
RouterOS version 6 allows to create, store and manage certificates in certificate store. Following example demonstrates how to easily manage certificates in RouterOS:
Make certificate templates
/certificate add name=ca-template common-name=myCa key-usage=key-cert-sign,crl-sign add name=server-template common-name=server add name=client1-template common-name=client1 add name=client2-template common-name=client2
Sign certificates and add CRL url. We will use IP address of the server as CRL URL.
/certificate sign ca-template ca-crl-host=10.5.101.16 name=myCa sign server-template ca=myCa name=server sign client1-template ca=myCa name=client1 sign client2-template ca=myCa name=client2
Note: If signing certificates on mipsbe cpu based devices(RB7xx,RB2011,RB9xx) then this process might take a while depending on key-size of specific certificate. With values 4k and higher, it might take a substantial time to sign a certificate.
If certificate does not have T flag then you need to set it as trusted before using it:
/certificate set myCa trusted=yes set server trusted=yes
Export client certificates with keys and CA certificate:
/certificate export-certificate myCa /certificate export-certificate client1 export-passphrase=xxxxxxxx /certificate export-certificate client2 export-passphrase=xxxxxxxx
Now these exported files can be imported on client machines.
If everything went well you should have something like this:
[admin@pe0] /certificate> print Flags: K - private-key, D - dsa, L - crl, C - smart-card-key, A - authority, I - issued, R - revoked, E - expired, T - trusted # NAME COMMON-NAME FINGERPRINT 0 K L A T myCa myCa 7fa636e6576495fe78f1a4... 1 K I T server server cf0650a291bf4685f2fbd3... 2 K I client1 client1 26233de30e89b203b946ab... 3 K I client2 client2 cf172b62201befaf8d8966...
Generate certificates with OpenSSL
Following is a step-by-step guide to creating your own CA (Certificate Authority) with openssl on Linux.
Note: Starting from v5.15 RouterOS supports pkcs8 key format. If you are using older versions, to import keys in pkcs8 format run command:
openssl rsa -in myKey.key -text and write key output to new file. Upload new file to RouterOS and import
- First step is to build the CA private key and CA certificate pair.
openssl genrsa -des3 -out ca.key 4096 openssl req -new -x509 -days 3650 -key ca.key -out ca.crt
During the process you will have to fill few entries (Common Name (CN), Organization, State or province .. etc). Created CA certificate/key pair will be valid for 10 years (3650 days).
Warning: If certificates are generated without key usage, you need to edit openssl.cnf file and specify what key usage to use, or create a new config file and use -config option while generating certificate.
- Now create private-key/certificate pair for the server
openssl genrsa -des3 -out server.key 4096 openssl req -new -key server.key -out server.csr openssl x509 -req -days 3650 -in server.csr -CA ca.crt -CAkey ca.key -set_serial 01 -out server.crt
Warning: RSA Key length must be at least 472 bits if certificate is used by SSTP. Shorter keys are considered as security threats.
And again during the process you will have to fill some entries. When filling CN remember that it must not match on CA and server certificate otherwise later naming collision will occur.
Note: Common Name (CN) in server certificate should match the the IP address of your server otherwise you will get "domain mismatch" message and for example Windows SSTP client will not be able to connect to the server. If clients are only Windows machines then CN can be a DNS name, too.
Note: If you are using "My ID user FQDN" in IpSec config then "subjectaltname" extension should be set on certificate, and must match the value set on remote peers "My ID user FQDN".
- Client key/certificate pair creation steps are very similar to server. Remember to Specify unique CN.
openssl genrsa -des3 -out client.key 4096 openssl req -new -key client.key -out client.csr openssl x509 -req -days 3650 -in client.csr -CA ca.crt -CAkey ca.key -set_serial 01 -out client.crt
To examine certificate run following command:
openssl x509 -noout -text -in server.crt -purpose
To import newly created certificates to your router, first you have to upload server.crt and server.key files to the router via FTP.
Now go to
/certificate submenu and run following commands:
[admin@test_host] /certificate> import file-name=server.crt passphrase: certificates-imported: 1 private-keys-imported: 0 files-imported: 1 decryption-failures: 0 keys-with-no-certificate: 0 [admin@test_host] /certificate> import file-name=server.key passphrase: certificates-imported: 0 private-keys-imported: 1 files-imported: 1 decryption-failures: 0 keys-with-no-certificate: 0
If everything is imported properly then certificate should show up with KT flag.
Note: If you want to use server certificates for OVPN or SSTP and use client certificate verification, then CA certificate must be imported, too.
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