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multiwalk2c

multiwalk2c is a multi-threaded SNMP scanner. It is modified version of snmpbulkwalk. It can scan agents listed in special agents file, write to single / many output files and traverse different parts of mib tree in one thread.

I wrote this program because I needed application to scan simultanously many snmp agents (like cable modems). Of course I could run many snmpbulkwalk instances in one time but it is heavy load solution. I've found great mass scanner - braa (http://s-tech.elsat.net.pl/braa/) which uses numerical mib representation. As I prefer string mib representation (like in snmpbulkwalk) I had to write such a tool myself. File(s) which multiwalk2c will output can be easily parsed using Perl, awk etc.

Usage: multiwalk2c -f agents.wlk [options]

multiwalk2c scans all agents found in special agents.wlk file. This file has one line agent:community syntax. See example file agents.wlk in the package. You can scan number of agents which is limited to the variable PTHREAD_THREADS_MAX. In my system this is 16384, which is really great number. If you're output context is multiple output each agent will write to its own file.

Possible options:
-s stack_rlimit - stack rlimit per thread in kb. Default stack size for process/thread

                     is about 8192 kb (ulimit -s) in many GNU/Linux distros. 
                     multiwalk2c changes soft limit to 512 kb to avoid consuming the whole
                     address space (which results "Resource temporary unavailable" message error).
-T total_timeout   - timeout in seconds. After that all threads are finished and
                     multiwalk2c exits.
-t timeout         - agent response timeout in seconds.
-r retries         - agent retries.
-o output          - output filename or directory. 
                     
                     In single file output contexts (multi file output = -m 0)
                     multiwalk2c can create PTHREAD_THREADS_MAX threads which write
                     to one single file. Some agents can response very slowly 
                     (what can't be acceptable sometimes - for example if you need
                      to feed rrd files every 5 minuts) and scanning will be stopped
                     after total_timeout. Your output parser has to know which agents
                     haven't be scanned to the end. Use then -e 1, which write 
                     'agent::=== END ===' to the output file.

                     In multi file output context (multi file output = -m 1) 
                     multiwalk2c will create separate files in directory 'output'.
                     Files have names 'agent.mwalk.part' (scanning agent is not complete
                     yet) and 'agent.mwalk' (agent was scanned successfully). 
                     As you see suffix .part describe if an output file is complete or not.
                     (Your management system can check output directory and analyze 
                     agents output files which are complete)
                     One problem you can discover is max open files limit (see ulimit -n)
                     if number of agents > open files limit). 
                     
-m multi_output      Controls if an output is single file output context (if you don't
                     specify default -m 0 is assumed) or multi file output (-m 1).
                     See '-o output' above what kind of output you'll get.

-n nice              Nice level - (default 20) if you don't want to kill you os leave it
                     untouched - see 'man renice', 'man getpriority'. 

-e endsignature      Controls if to output will be write signature 'agent::=== END ==='.
                     This signature will be write only if agent will return all requested
                     mibs. In multi file output you don't need output signature, because
                     not completed scans has suffix .part in output directory.
                     Value endsignature can be 0 (don't write signature) or 1 (write it).

-O output_type       Output type in snmpbulkwalk style (see snmpbulkwalk -O args).

-L miblist           Mibs to walk, ex. -L system,if,docsIfCmObjects

-C r<NUM>|n<NUM>     Set r-repeaters to <NUM>, n-nonrepeaters to <NUM>.

multiwalk2c

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