Solved: snmp traps

shaikh.zaid22 · ‎04-17-2023

hi all,

i have configured 4 snmp hosts in the catalyst switch as my NAC appliances for traps forwarding.

i need to know how the cisco switch forwards the snmp-traps to several hosts ? is it the first host configured will serve all the request and forward the traps or all the active hosts?

Also, if i failover the first host, will the switch be still sending the traps to that(failed) host as well?

Insights from an expert

marce1000 · ‎04-17-2023

>...i need to know how the cisco switch forwards the snmp-traps to several hosts ? i
Probably done sequentially depended on how they are defined (in which order) in the running-config , if you have milliseconds based logging on the snmp managers , you may be able to find out

>...Also, if i failover the first host, will the switch be still sending the traps to that(failed) host as well?
Yes , meaning it's actually not related because SNMP traps are UDP and UDP is stateless ,the switch 'just sends it' , without caring if it arrived (because UDP is used) ,

M.

-- Each morning when I wake up and look into the mirror I always say ' Why am I so brilliant ? '
When the mirror will then always repond to me with ' The only thing that exceeds your brilliance is your beauty! '

View solution in original post

marce1000 · ‎04-17-2023

>...i need to know how the cisco switch forwards the snmp-traps to several hosts ? i
Probably done sequentially depended on how they are defined (in which order) in the running-config , if you have milliseconds based logging on the snmp managers , you may be able to find out

>...Also, if i failover the first host, will the switch be still sending the traps to that(failed) host as well?
Yes , meaning it's actually not related because SNMP traps are UDP and UDP is stateless ,the switch 'just sends it' , without caring if it arrived (because UDP is used) ,

M.

-- Each morning when I wake up and look into the mirror I always say ' Why am I so brilliant ? '
When the mirror will then always repond to me with ' The only thing that exceeds your brilliance is your beauty! '

shaikh.zaid22 · ‎04-17-2023

Thanks marce.

You are right since its a udp switch is just forwarding as is.

MHM Cisco World · ‎04-17-2023

SNMP is UDP and all protocol that need broadcast use UDP and hence the SW send multi copy of packet to all SNMP server
except that even if multi copy still this add more work in CPU.

Flavio Miranda · ‎04-17-2023

Hi

The switch will send to all host independently and if the host fail the switch does not care, it will try to send anyway unless you do there and remove the host. There is not cheking or load balance service on it.

And keep in mind that SNMP traffic uses UDP protocol and UDP does not provide confirmation. Would be like a stream, device send data and that´s it. If receive or not, it does not care.