question

tesius avatar image
tesius asked tesius answered

Why do I keep getting authentication errors in my iTest SNMPv3 session?

In a test orchestration project based on iTest 9.3, I created an SNMP session for a device, of which I would like to pull performance parameters over SNMPv3.

Unlike as with snmpwalk (used on Ubuntu over WSL), I am unable to authenticate properly, since I always get an SNMP Error, indicating that either some credentials or, the community string is wrong.

However, I triple-checked all entered credentials and authentication settings but still keep getting an SNMP authentication error, when I try to run getValue command using the SNMP session.

My working snmpwalk example looks as follows:

$ snmpwalk -m +[name of the custom MIB module] -v3 -l authPriv -u [username] -a SHA512 -A [password] -x AES -X [key] -E [community string] [IP]:161 [MIB tree OID]

To reproduce the above (perfectly working) SNMPv3 authentication in the iTest SNMP session, I filled in the following authentication parameters in Edit Session Profile:

  • agent device's IP address
  • SNMP port = 161
  • SNMP Version = Version 3
  • username & auth pw

--- as well as under More >> Authentication (SNMPv3 only) ---

  • V3 Context: = [community string]
  • Security level = Authentication, privacy
  • Authentication algorithm = SHA
  • Privacy -> Password:= [key]
    • AES-128 / -192 / -256 (not working with either of them)

I used Wireshark to analyze the UDP packets issued by the above snmpwalk command and compared them to the corresponding getValue SNMP packets issued using the iTest Session:

Interestingly enough, the packets' encoded authentication parameters (msgAuthenticationParameters) have a significant difference in terms of size, namely; In the snmpwalk case, these encoded parameters have a length of 48 B, while in the iTest case (for all selectable AES methods), the msgAuthenticationParameters are always only 12 B.

Does anybody have an idea, if I should correct anything in my session profile to get a working iTest SNMP session or, whether this potentially a bug in iTest 9.3?

iTestsession profileWiresharksnmpauthentication
10 |950

Up to 2 attachments (including images) can be used with a maximum of 512.0 KiB each and 1.0 MiB total.

1 Answer

·
tesius avatar image
tesius answered

Dear Spirent forum community, I haven't heard from any of the 70 question subscribers for over a month unfortunately.

I would be really glad if any of you 70 could at least send me a read confirmation, so I can be assured, the forum is working fine.

Thank you in advance!

10 |950

Up to 2 attachments (including images) can be used with a maximum of 512.0 KiB each and 1.0 MiB total.

Write an Answer

Hint: Notify or tag a user in this post by typing @username.

Up to 2 attachments (including images) can be used with a maximum of 512.0 KiB each and 1.0 MiB total.