Re: Timeout while DNS lookups fail

Yes, informsink (not infosink), trapsink and trapess are snmpd.conf 
parameters that take a host trap receiver as argument. If this host is by 
name, it will try to query DNS.

Hosts is good and negates any DNS query.

If you don't have any IP address or hostnames, where do you get the reverse 
DNS lookup then?

What OS are you using and what is your hosts entry in /etc/nsswitch.conf?

DNS lookups (reverse or straight) are always application dependent, never 
OS. That means that explicit code in the application is used to invoke it. 
DNS implementation is OS depended. Smtp servers (mail) use reverse DNS 
sometimes to verify sender address.

BR,
Nikos
----- Original Message ----- 
From: "Pete Kelly" <[email protected]>
To: <[email protected]>
Sent: Wednesday, December 31, 2008 1:25 AM
Subject: Re: Timeout while DNS lookups fail


>I don't follow the "Try specifying infosink or trapess by IPaddress"
> comment.  Is this referencing net-snmp configuration settings?
>
> There is nothing on the machine on which net-snmp is running, that
> references either an IP address or a name for the trap senders
> specifically to try and eliminate any DNS lookups.  That includes hosts,
> bind, or resolv.conf.
>
> Thanks,
> Pete
>
> Nikos Balkanas wrote:
>> Try specifying infosink or trapess by IPaddress. It shouldn't query DNS
>> if address is already in dotted format.
>>
>> Cheers,
>> Nikos
>> ----- Original Message ----- From: "Pete Kelly" <[email protected]>
>> To: <[email protected]>
>> Sent: Tuesday, December 30, 2008 1:37 AM
>> Subject: Timeout while DNS lookups fail
>>
>>
>>> Greetings:
>>>
>>> We are using the tools to collect traps from telephone network
>>> equipment, think cabinet along the highway, where there are lots (could
>>> be hundreds or thousands) of devices, none of which have a reverse DNS
>>> lookup entry.
>>>
>>> There appears to be a mechanism where, with no named running (not
>>> installed) and with an empty resolv.conf file, the traps get delayed
>>> while a reverse DNS query times out.  There appears to be little or no
>>> delay when there are few traps but with numerous devices and many traps
>>> the delay can get quite lengthy.
>>>
>>> Is there a setting to disable this behavior in net-snmp?
>>> or
>>> Is this even a behavior of net-snmp but rather is it related to the
>>> operating system?
>>>
>>> Thanks,
>>> Pete
>>> -- 
>>> Pete Kelly
>>> Cordell Inc.
>>> 909-971-9100
>>>
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