i try to monitor mikrotik router within branch (behind 4G modem) and getting this:
24064:20150715:215941.419 item "mikrotik:ssh.run[pppAccessTechnology]" became supported
24065:20150715:220040.582 error reason for "mikrotik:ssh.run[pppCurrentOperator]" changed: Cannot obtain authentication methods: Would block requesting userauth list
24066:20150715:220040.721 item "mikrotik:ssh.run[pppAccessTechnology]" became not supported: Cannot establish SSH session: Unable to exchange encryption keys
24065:20150715:220050.669 error reason for "mikrotik:ssh.run[pppModemStatus]" changed: Cannot establish generic session channel
24064:20150715:220442.081 error reason for "mikrotik:ssh.run[pppAccessTechnology]" changed: Password authentication failed: Would block waiting
24064:20150715:220541.099 error reason for "mikrotik:ssh.run[pppCurrentOperator]" changed: Cannot establish SSH session: Unable to exchange encryption keys
24064:20150715:220543.970 error reason for "mikrotik:ssh.run[pppFunctionality]" changed: Cannot establish SSH session: Unable to exchange encryption keys
24066:20150715:220553.435 error reason for "mikrotik:ssh.run[pppModemStatus]" changed: Cannot establish SSH session: Unable to exchange encryption keys
24064:20150715:220940.626 item "mikrotik:ssh.run[pppAccessTechnology]" became supported
24064:20150715:221042.337 item "mikrotik:ssh.run[pppAccessTechnology]" became not supported: Cannot establish SSH session: Unable to exchange encryption keys
24064:20150715:221045.696 error reason for "mikrotik:ssh.run[pppFunctionality]" changed: Cannot establish SSH session: Failed getting banner
24064:20150715:221045.696 item "mikrotik:ssh.run[pppManufacturer]" became not supported: Cannot establish SSH session: Unable to exchange encryption keys
24064:20150715:221050.478 item "mikrotik:ssh.run[pppModel]" became not supported: Cannot establish SSH session: Unable to exchange encryption keys
24064:20150715:221440.644 item "mikrotik:ssh.run[pppAccessTechnology]" became supported
24064:20150715:221542.457 item "mikrotik:ssh.run[pppAccessTechnology]" became not supported: Cannot establish SSH session: Unable to exchange encryption keys
24064:20150715:221940.375 error reason for "mikrotik:ssh.run[pppAccessTechnology]" changed: Password authentication failed: Authentication failed (username/password)
24064:20150715:222044.039 error reason for "mikrotik:ssh.run[pppFrameErrorRate]" changed: Cannot obtain authentication methods: Would block requesting userauth list
24065:20150715:222044.727 error reason for "mikrotik:ssh.run[pppFunctionality]" changed: Cannot establish SSH session: Unable to exchange encryption keys
24064:20150715:222048.670 error reason for "mikrotik:ssh.run[pppManufacturer]" changed: Cannot obtain authentication methods: Would block requesting userauth list
24064:20150715:222540.380 error reason for "mikrotik:ssh.run[pppCurrentOperator]" changed: Password authentication failed: Authentication failed (username/password)
24064:20150715:222542.472 error reason for "mikrotik:ssh.run[pppFrameErrorRate]" changed: Cannot establish SSH session: Unable to exchange encryption keys
24067:20150715:222546.947 error reason for "mikrotik:ssh.run[pppManufacturer]" changed: Cannot establish SSH session: Unable to exchange encryption keys
24064:20150715:223041.162 error reason for "mikrotik:ssh.run[pppCurrentOperator]" changed: Cannot obtain authentication methods: Would block requesting userauth list

looks like i have too long login process, for example
$ time ssh [email protected] "system clock print"
time: 22:24:14
date: jul/15/2015
time-zone-autodetect: no
time-zone-name: Europe/Moscow
gmt-offset: +03:00

real 0m2.841s
user 0m0.093s
sys 0m0.036s

so 2,8 it's just for login.

i thinks zabbix must have tunnable options for some cases like this ( 3G/LTE quality networks ). it can be tunnable per item...