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[MX] "SNMPD_AUTH_FAILURE: agent_io_reader: failed input interface authorization" log message



Article ID: KB35513 KB Last Updated: 03 Mar 2020Version: 1.0

This article gives the reason for the "SNMPD_AUTH_FAILURE" log message to be seen on MX Series routers and recommends the ideal configuration to prevent this log message.



Simple Network Management Protocol (SNMP) has been configured and the following log message is seen on the device:

"SNMPD_AUTH_FAILURE: agent_io_reader: failed input interface authorization from 10.x.x.x to 10.x.x.x"

Check whether SNMP requests are restricted to the interface list. If the requests come from a non-listed interface, the above log message is expected.

snmp {
     location XXXX;
     contact "";
     community Test {
         authorization read-only;
         clients {



Specify the names of any logical or physical interfaces that should have SNMP access privileges. Any SNMP requests that enter the router or switch from interfaces that are not listed are discarded.

If you identify that SNMP server is reachable via any interface, include that interface in SNMP:

lab@MX> show route

inet.0: 814509 destinations, 4668764 routes (805294 active, 2 holddown, 2728493 hidden)
+ = Active Route, - = Last Active, * = Both      *[OSPF/150] 2w1d 02:05:09, metric 116, tag 0
                     to via xe-0/0/4.0
                   > to via xe-0/0/6.0
                     to via xe-0/1/4.0
                     to via xe-0/1/6.0

#set snmp interface xe-0/0/6.0

If you see SNMP requests from ‚Äčnon-authorized IPs, configure a firewall filter to discard packets from the source that you do not want to authorize.


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