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Tom O'Connor
Asked: 2012-06-13 06:37:49 +0800 CST

SNMP Extend not working

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I've got a server running Postgresql 9.1 replication. I wrote a script which prints out the current replication lag (master inserts a unix timestamp every 60s, and the slave compares it to the current timestamp).

I've added 

extend replag /usr/local/bin/check_lag_quietly.sh

to snmpd.conf, and restarted the snmpd service, but when I snmpwalk the host, either from localhost, or from another machine on the network, I can see all of the other OIDs, but not this one.
If I do SNMP-Get as 

tom.oconnor@charcoal-black:~$ snmpget -v2c -cpublic dns-2 UCD-SNMP-MIB::extTable
UCD-SNMP-MIB::extTable = No Such Object available on this agent at this OID

Then it can't find the OID there either.

Net-SNMP version 5.4.2.1, Ubuntu 10.04.

snmpd ubuntu-10.04

2 Answers

  1. Best Answer

    On Debian with 5.4.3 snmpd dosn't seem to load all it's modules by default, by adding:

    -I interface,ifTable,ifXTable,cpu,cpu_linux,hw_mem,extend,versioninfo,snmp_mib,ip,at,system_mib

    to the command line for snmpd (note the 'extend' in there), i can:

    snmpwalk -Ou  -v 1 -c public localhost nsExtendOutput2Table

    which returns the default 'extend' examples:

    enterprises.netSnmp.netSnmpObjects.nsExtensions.nsExtendObjects.nsExtendOutput2Table.nsExtendOutput2Entry.nsExtendOutLine."test1".1 = STRING: Hello, world!
enterprises.netSnmp.netSnmpObjects.nsExtensions.nsExtendObjects.nsExtendOutput2Table.nsExtendOutput2Entry.nsExtendOutLine."test2".1 = STRING: Hello, world!
enterprises.netSnmp.netSnmpObjects.nsExtensions.nsExtendObjects.nsExtendOutput2Table.nsExtendOutput2Entry.nsExtendOutLine."test2".2 = STRING: Hi there

    Which is close to what you want.

    You can get a list of all the snmpd modules with:

    snmpd -Dmib_init -H

    I guess the real question here is "How do i get snmpd to load all it's modules by default"

    • 4

  2. We need to enable agent/extend module while configuring the pkg.

    ./configure --with-default-snmp-version=2 --with-logfile=/var/log/snmpd.log --with-sys-location= --with-sys-contact= --with-persistent-directory=/home/swuser/snmp --with-mibs=RFC1213-MIB --with-mibdirs= --disable-scripts --with-out-mib-modules=examples/ucdDemoPublic,mibII/system_mib --without-kmem-usage --disable-mibs --disable-mib-loading --disable-manuals --without-perl-modules --enable-shared --host=arm-none-linux-gnueabi --with-cc=arm-none-linux-gnueabi-gcc --target=arm-none-linux-gnueabi --disable-embedded-perl --with-ar=arm-none-linux-gnueabi-ar --with-mib-modules="ucd-snmp/dlmod"

    Here if you can disable agent/extend module by --with-out-mib-modules=agent/extend or else by default it's enabled in net-snmp-5.7

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