Month: October 2008

How-To: SNMP for Mac and Linux

How-To: SNMP for Mac and Linux

Note-taking time.. Again, some stuff i don’t usually use or encounter, so i better log them.. for future use.


  • yum -y install snmp
  • vi /etc/snmp/snmpd.conf
  • replace community string
  • service snmpd start
  • chkconfig snmpd on
  • ps ax| grep snmp: /usr/sbin/snmpd -Lsd -Lf /dev/null -p /var/run/ -a

Mac OS X 10.4 Xserve

  • From command land: snmpconf
  • Copy snmpd.conf (generated from snmpconf) to /usr/share/snmp/ folder
  • vi /etc/hostconfig
  • Edit and set to yes: SNMPSERVER=-YES-
  • Reboot.. or start snmpd (/usr/sbin/snmpd)
  • Test: snmpwalk -v1 -c <your-community-string>

To allow snmp in iptables:

$IPTABLES -A INPUT -p udp -s 0/0 –sport 1024:65535 -d $INTIP –dport 161:162 -m state –state NEW,ESTABLISHED -j ACCEPT
$IPTABLES -A OUTPUT -p udp -s $INTIP –sport 161:162 -d 0/0 –dport 1024:65535 -m state –state ESTABLISHED -j ACCEPT

How-To: Troubleshoot NFS

How-To: Troubleshoot NFS

I’ve been using NFS ever since but not exactly the one to set up the server. When the ff. problem occurred, I never imagined I have very little idea as to where to start troubleshooting: Could not chdir to home directory /home/User: No such file or directory.

Well i know the directory’s shared via NFS from another server, so i had to start from there. So here’s a short list of things to check or do (Redhat/Fedora/CentOS based):

On the server:

  1. Make sure NFS is running. Two services should be running: portmap and the NFS service. Try to restart the services.
  2. portmap: /etc/init.d/portmap restart
    nfs: /etc/init.d/nfs restart
    Check if it runs at startup.
    chkconfig --list | grep nfs
    chkconfig nfs on

  3. Check /etc/exports. This is a list of shared volumes
  4. /export,sync,root_squash,no_wdelay,no_subtree_check,secure)

  5. Check /etc/hosts.allow and /etc/hosts.deny. Lists allowed remote and denied clients to access the server.
  6. ALL:

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Google's Wikimapia

Google's Wikimapia

Finally, the feature that’s been missing from Google Maps. I knew it, someday Google will realize it and work on it.

They used to have something like you can add a marker/point to a place but i found it lacking. Rather, I used to check out Wikimapia for finding directions around Metro Manila. Although i find it cluttered with unnecessary comments (sometimes funny, at times quite offensive), at least it did its part for me.. specifically, when i had to go to Cubao, Makati, and The Fort.

Google Map Maker was actually launched in (or rather extended to) 17 countries including the Philippines on Sept. 25 (see announcement). I didn’t know that until just now.. But anyway, i find it

  • very detailed — complete with information, street, building type
  • more reliable — changes/updates are being moderated
  • more organized — at least for now, and they are planning to keep it that way

Cheers to this one!

Space Elevator in 20 Years

Space Elevator in 20 Years

I can be a space & astronomy geek sometimes. Just reading about the space elevator that was on the news recently brought out that little fangirl who once dreamed of becoming an astronomer herself.. (heck, don’t blame me, i was still a kid then. if i hadn’t disposed of the idea, i might even be dreaming to be an astronaut. haha!)

Space elevator, the term itself is an overwhelming load of science fiction. I’m sure we’ve all heard about this before, perhaps more as a concept. But with support from top engineers worldwide – Japan and European countries in the forefront – this whole idea is more concrete than ever. There are even conferences and competitions coming up by 4th quarter of this year. How cool is that?

I’ll make this sound easy. With all the bright minds at work, now they only need to extend a 100,000 km. cable to the space. How do they think it can be accomplished? Carbon Nanotubes.

Carbon nanotubes (CNTs) are allotropes of carbon with a nanostructure that can have a length-to-diameter ratio greater than 1,000,000. (source: wikipedia)

While i don’t really foresee this in the very near future (20 years of waiting time is well worth the wait though), I would extremely LOVE IT if i can witness the space elevator in full reality during my lifetime. But then of course, perhaps i won’t be able to afford it. Pity.

Anyway, fangirls and boys, geeks and geekettes, you can all check out their blog at the website, friend them in facebook, and follow them on twitter.