Hi,

We use a Cisco 7200 router for our PPPOE users. As they login cisco creates a virtual interface for the user. we want to trac their internet traffic over this router but when a user logout and login again cisco creates a different cirtual interface for the user so prtg cannot monitor the user and says no such name. In radius we are sending "lcp:interface-config#3=desc USERNAME" to router so there is an always description for user which does not matter in which virtual interface he is. But we could not manage prtg to continue to get the snmp traffic of that user as it gets interface number for traccing user not description. I tried all port identification methods but nothing helped.

Article Comments

Hello,

thank you very much for your KB-Post. Does anything persist about such a virtual interface (the ifalias or the ifdescr)?

best regards.


Aug, 2013 - Permalink

we push customer PPPOE account name as ifalias to router and ifalias of the account never changes, but as ports are created virtually everytime virtual port changes. So we need to be able to collect traffic from ifalias.

When a PPPOE account logs out and logs in back, PRTG says "No Such Name(SNMP error# 2)" when I click the sensor and check settings it shows Under "Traffic Specific - Interface number" as like "415:vi30" which was on virtual interface 30 in his last login/auto discovery

Thanks Cenk


Aug, 2013 - Permalink

Which exact version of PRTG are you using? Can you please check the "Settings" of an old and new SNMP Traffic Sensor for the same account/user? Are there any differences in the "Interface"-field?


Aug, 2013 - Permalink

Version is PRTG Network Monitor 13.2.3.2285

In logged out snmp sensor, Interface number is: 415:vi30 In logged in (new sensor), Interface number is: 411:vi26


Aug, 2013 - Permalink

In interfaces it writes;

In new logged in; 403:3c1b_Misafir In old logged out: 482:3c1b_Misafir

and PRTG version is: PRTG Network Monitor 13.2.3.2285


Aug, 2013 - Permalink

Please try updating to version 13.3.5, does this then help?


Aug, 2013 - Permalink

I have updated prtg but nothing changed. I have deleted all sensors on that router and made an autodiscover. prtg found all logged in user traffic sensors. The I have logged out a user and logged in back and made another autodiscover.

It found new sensor for the logged in user and says "no such name" for old sensor.

Traffic specific Interface number for new: 415:EBI_INTERNET Interface number for old: 473:EBI_INTERNET


Aug, 2013 - Permalink

The problem is, that ifindexes (interface numbers) should only change upon a reboot of the device, and that seems not the case here. So it's not according to SNMP standard, and so PRTG cannot detect this sadly.


Aug, 2013 - Permalink