Manually install custom mib file into debian

Download mikrotik MIB:
https://download2.mikrotik.com/Mikrotik.mib

Look for dir where default mibs is placed: 
find / -name mibs
This will show something like: 
/var/lib/snmp/mibs
/usr/share/snmp/snmpconf-data/snmp-data/mibs
/usr/share/snmp/mibs
Move to the possible mibs directory: 
cd /usr/share/snmp/mibs
Check the content. 
ls -l
This will show something like: 
-rw-r--r-- 1 root root  1913 Jan 24  2017 GNOME-SMI.txt
lrwxrwxrwx 1 root root    23 Sep  1  2016 iana -> /var/lib/snmp/mibs/iana
-rw-r--r-- 1 root root  6845 Dec  8  2014 IANA-ADDRESS-FAMILY-NUMBERS-MIB.txt
-rw-r--r-- 1 root root 32837 Dec  8  2014 IANAifType-MIB.txt
-rw-r--r-- 1 root root  4389 Dec  8  2014 IANA-LANGUAGE-MIB.txt
-rw-r--r-- 1 root root  3803 Dec  8  2014 IANA-RTPROTO-MIB.txt
lrwxrwxrwx 1 root root    23 Sep  1  2016 ietf -> /var/lib/snmp/mibs/ietf
-rw-r--r-- 1 root root  5931 Dec  8  2014 LM-SENSORS-MIB.txt
-rw-r--r-- 1 root root 15901 Dec  8  2014 NET-SNMP-AGENT-MIB.txt
-rw-r--r-- 1 root root  9160 Dec  8  2014 NET-SNMP-EXAMPLES-MIB.txt
-rw-r--r-- 1 root root  9326 Dec  8  2014 NET-SNMP-EXTEND-MIB.txt
-rw-r--r-- 1 root root  2036 Dec  8  2014 NET-SNMP-MIB.txt
-rw-r--r-- 1 root root  1215 Dec  8  2014 NET-SNMP-MONITOR-MIB.txt
-rw-r--r-- 1 root root  3350 Dec  8  2014 NET-SNMP-PASS-MIB.txt
-rw-r--r-- 1 root root  2504 Dec  8  2014 NET-SNMP-PERIODIC-NOTIFY-MIB.txt
-rw-r--r-- 1 root root  1226 Dec  8  2014 NET-SNMP-SYSTEM-MIB.txt
-rw-r--r-- 1 root root  4814 Dec  8  2014 NET-SNMP-TC.txt
-rw-r--r-- 1 root root  5039 Dec  8  2014 NET-SNMP-VACM-MIB.txt
-rw-r--r-- 1 root root  1174 Dec  8  2014 RFC-1215.txt
-rw-r--r-- 1 root root 43927 Dec  8  2014 SNMP-TLS-TM-MIB.txt
-rw-r--r-- 1 root root  8912 Dec  8  2014 SNMP-TSM-MIB.txt
-rw-r--r-- 1 root root  2163 Dec  8  2014 UCD-DEMO-MIB.txt
-rw-r--r-- 1 root root  4613 Dec  8  2014 UCD-DISKIO-MIB.txt
-rw-r--r-- 1 root root  3087 Dec  8  2014 UCD-DLMOD-MIB.txt
-rw-r--r-- 1 root root  6476 Dec  8  2014 UCD-IPFILTER-MIB.txt
-rw-r--r-- 1 root root  8118 Dec  8  2014 UCD-IPFWACC-MIB.txt
-rw-r--r-- 1 root root 18274 Dec  8  2014 UCD-SNMP-MIB-OLD.txt
-rw-r--r-- 1 root root 49561 Dec  8  2014 UCD-SNMP-MIB.txt
Download new mib file: 
curl "http://download2.mikrotik.com/Mikrotik.mib" > Mikrotik.txt
Edit configuration: 
vi /etc/snmp/snmp.conf
Add new line: 
mibs +/usr/share/snmp/mibs/Mikrotik.txt
Try the test walk: 
snmpwalk -v2c -cpublic 192.168.88.1 -OfT
Byat