Re: [tkined] Passing Original IP address on.

Juergen Schoenwaelder (schoenw@ibr.cs.tu-bs.de)
Mon, 9 Feb 1998 11:01:04 +0100

>>>>> Richard Swain writes:

Richard> I am using scotty(2.1.7)/tnm(8.0)/tcl(8.0) to receive SNMP
Richard> trap data from devices.

Richard> I receive the data, parse it with tcl scripts and then
Richard> forward it to a central location for additional proceessing
Richard> and storage.

Richard> The problem is that the original IP address from the device
Richard> is say, 192.1.1.123 and after the scripts process it and pass
Richard> it on the final destination sees it as the scripts machine
Richard> say 192.1.1.99.

Richard> Is there a way to save the incoming IP address, parse the
Richard> data with the scripts and then just before sending put the
Richard> saved IP address in as the source address in the IP header ?

This is a know problem of the SNMPv2 <-> SNMPv1 conversion. Scotty's
API is based on SNMPv2/SMIv2 and suffers from this more general
problem. I hope that the SNMPv3 WG will address this issue when
updating RFC 1907. There should be two more objects:

snmpTrapDomain OBJECT-TYPE
SYNTAX TDomain
MAX-ACCESS accessible-for-notify
STATUS current
DESCRIPTION
"The transport domain associated with the trap currently
being sent. When a SNMPv2 proxy agent is mapping an RFC1157
Trap-PDU into a SNMPv2-Trap-PDU, this variable occurs as
next to next to last varbind."
:: { snmpTrap 5 }

snmpTrapAddress OBJECT-TYPE
SYNTAX TAddress
MAX-ACCESS accessible-for-notify
STATUS current
DESCRIPTION
"The transport address associated with the trap currently
being sent. When a SNMPv2 proxy agent is mapping an RFC1157
Trap-PDU into a SNMPv2-Trap-PDU, this variable occurs as
next to last varbind."
:: { snmpTrap 6 }

I will send a message to the SNMPv3 WG and ask what they think about
it. If people on the SNMPv3 WG agree that this is the way to go, I
will add support for this conversion into the sources currently under
development.
Juergen

-- 
Juergen Schoenwaelder  schoenw@ibr.cs.tu-bs.de http://www.cs.tu-bs.de/~schoenw
Technical University Braunschweig, Dept. Operating Systems & Computer Networks
Bueltenweg 74/75, 38106 Braunschweig, Germany.        (Tel. +49 531 / 391 3283)
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