CentOS - Apr 2009 - One for the Cisco experts...

I have a Cisco 6509 switch that I'm monitoring with SNMP from a
CentOS5 machine.  SNMP polls are the only access I have to this
device, we are not allowed to log on via telnet.

How can I find out which port on the switch a particular server is
connected to?  I was hoping that this is somehow possible using the
mac address and the data gathered from snmpwalk/snmpget requests but
I'm not having much luck.  How would you tackle this problem?

Quoting Sean Carolan <scarolan at gmail.com>:
> I have a Cisco 6509 switch that I'm monitoring with SNMP from a
> CentOS5 machine.  SNMP polls are the only access I have to this
> device, we are not allowed to log on via telnet.
>
> How can I find out which port on the switch a particular server is
> connected to?  I was hoping that this is somehow possible using the
> mac address and the data gathered from snmpwalk/snmpget requests but
> I'm not having much luck.  How would you tackle this problem?
This might help:

<http://www.linuxdynasty.org/howto-find-the-port-on-a-switch-that-a-host-belongs-to-the-easy-way-part-1.html>

On Tue, Apr 21, 2009 at 11:44:47AM -0500, Sean Carolan wrote:
 
> How can I find out which port on the switch a particular server is
> connected to?  I was hoping that this is somehow possible using the
> mac address and the data gathered from snmpwalk/snmpget requests but
> I'm not having much luck.  How would you tackle this problem?
My notes: http://wiki.xdroop.com/space/snmp/Switching+Tables

Basically there are at least two places in snmp where this might be
stored.  The most obvious is the classic MIB-II Bridge.  The wrinkle
with this MIB is that some switches maintain separate tables for each
VLAN, which means in order to query the switch properly, you have to
query the MIB for each VLAN.

Newer switches populate the Q-Bridge-MIB instead of or as well as the
MIB-II Bridge.  This table contains the VLAN that the target MAC is
reachable through, which is useful since you don't have to know it
ahead of time.

We have a six- or seven- year old cisco 3750 which is running an IOS
which doesn't have the newer MIB; for this switch, we must explicitly
query the MIB-II Bridge for each VLAN.  I would hope that newer
relesaes of IOS wouldn't have this limitation.

-- 
 /\oo/\
/ /()\ \ David Mackintosh | 
         dave at xdroop.com  | http://www.xdroop.com
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Sean Carolan wrote:
> I have a Cisco 6509 switch that I'm monitoring with SNMP from a
> CentOS5 machine.  SNMP polls are the only access I have to this
> device, we are not allowed to log on via telnet.
> 
> How can I find out which port on the switch a particular server is
> connected to?  I was hoping that this is somehow possible using the
> mac address and the data gathered from snmpwalk/snmpget requests but
> I'm not having much luck.  How would you tackle this problem?
Uncomment the Linkd service in service-configuration.xml.  Then, at 
least if the connected device is also monitored the 'View Node Link 
Detailed Info' link on the node screen will show the connected device.

-- 
   Les Mikesell
    lesmikesell at gmail.com

> We have a six- or seven- year old cisco 3750 which is running an IOS
> which doesn't have the newer MIB; for this switch, we must explicitly
> query the MIB-II Bridge for each VLAN. ?I would hope that newer
> relesaes of IOS wouldn't have this limitation.
This is exactly what I was missing.  Thank you, I am now able to track
down which port each device is on.

> My notes: http://wiki.xdroop.com/space/snmp/Switching+Tables
>
Hi Dave, so using the example from your site above I tested a mac
address against one of our switches:

[scarolan at host:~]$ snmpwalk -v1 -c public at 200 10.100.3.6
.1.3.6.1.2.1.17.4.3 | grep `hexmac2decoid 00:B0:D0:E1:BF:52`
SNMPv2-SMI::mib-2.17.4.3.1.1.0.176.208.225.191.82 = Hex-STRING: 00 B0
D0 E1 BF 52
SNMPv2-SMI::mib-2.17.4.3.1.2.0.176.208.225.191.82 = INTEGER: 389
SNMPv2-SMI::mib-2.17.4.3.1.3.0.176.208.225.191.82 = INTEGER: 3

Does this mean that the machine is plugged into port 389?  I didn't
think there were 389 ports on the switch.

> How can I find out which port on the switch a particular server is
> connected to?  I was hoping that this is somehow possible using the
> mac address and the data gathered from snmpwalk/snmpget requests but
> I'm not having much luck.  How would you tackle this problem?
>   
Take a look at Netdisco. I seem to remember it's a little tricky to set
up on CentOS but I wouldn't live without it now.

http://www.netdisco.org/

Dan

----- "Daniel Bird" <dbird at sgul.ac.uk> escreveu:
> > How can I find out which port on the switch a particular server is
> > connected to?  I was hoping that this is somehow possible using the
> > mac address and the data gathered from snmpwalk/snmpget requests
> but
> > I'm not having much luck.  How would you tackle this problem?
> >   
> Take a look at Netdisco. I seem to remember it's a little tricky to
> set
> up on CentOS but I wouldn't live without it now.
> 
> http://www.netdisco.org/
> 
Hi List,

   Well after following the "little tricky" :D install scripts on
this address: http://www.auburn.edu/~gouldwp/netdisco/ 

   I had this error: "failed to resolve handler `netdisco::Mason':
Can't locate netdisco/Mason.pm in @INC"
on my httpd error_log file. Anyone had sucess on made netdisco running ?
My problem (apparently) was only on the WebCli. And after I had the work to put 
it all together I was hopping I can see their face :D

   On the other hand, I will try OpenNMS and ZenoOS ASAP :D

       Thanks in advance,

          Antonio.

-- 
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| Antonio S. Martins Jr. - Support Analist | "Only The Shadow Knows     |
| Universidade Estadual de Maring?? - Brasil|   what evil lurks in the   |
| NPD - N??cleo de Processamento de Dados   |       Heart of Men!"       |
| E-Mail: asmartins at uem.br / shadow at uem.br | !!! Linux User: 52392 !!!  |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     "Real Programmers don???t need comments ??? the code is obvious."

-- 
Esta mensagem foi verificada pelo sistema de antiv?rus e
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----- "Antonio da Silva Martins Junior" <asmartins at uem.br>
escreveu:
> ----- "Daniel Bird" <dbird at sgul.ac.uk> escreveu:
> 
> > > How can I find out which port on the switch a particular server
> is
> > > connected to?  I was hoping that this is somehow possible using
> the
> > > mac address and the data gathered from snmpwalk/snmpget requests
> > but
> > > I'm not having much luck.  How would you tackle this problem?
> > >   
> > Take a look at Netdisco. I seem to remember it's a little tricky
to
> > set
> > up on CentOS but I wouldn't live without it now.
> > 
> > http://www.netdisco.org/
> 
> 
>    Well after following the "little tricky" :D install scripts on
> this address: http://www.auburn.edu/~gouldwp/netdisco/ 
> 
>    I had this error: "failed to resolve handler `netdisco::Mason':
> Can't locate netdisco/Mason.pm in @INC" 
> on my httpd error_log file. Anyone had sucess on made netdisco running?
> 
Hi List,

   Well nothing better than post an email to the list to find the solution:

   The install script I was using (following) from the site above, put
two include lines (from netdisco_apache.conf and netdisco_apache_dir.conf)
on the end of "/etc/httpd/conf/httpd.conf". But it generates some
errors on
the httpd programa, and I moved them to links on "/etc/httpd/conf.d"
to the
netdisco config files.
 
   The problem was "netdisco*" was load before "perl*" and
then the errors.

   Quick solution: rename "netdisco*" to "zz_netdisco*", now
the load order
are OK and the WebCli are running.


    Thanks for the help,

         Antonio.

-- 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Antonio S. Martins Jr. - Support Analist | "Only The Shadow Knows     |
| Universidade Estadual de Maring?? - Brasil|   what evil lurks in the   |
| NPD - N??cleo de Processamento de Dados   |       Heart of Men!"       |
| E-Mail: asmartins at uem.br / shadow at uem.br | !!! Linux User: 52392 !!!  |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     "Real Programmers don???t need comments ??? the code is obvious."

-- 
Esta mensagem foi verificada pelo sistema de antiv?rus e
 acredita-se estar livre de perigo.