Archive for February, 2011

Debugging dns problems

Thursday, February 17th, 2011

Recently I faced a DNS problem in a complex setup. I had a very locked down jumphost with one public network and two internal networks and a very nazi firewall controlling what packets went in an out.

On the inside I had a linux machine running BIND, also with a firewall and a locked down setup.

On yet another host on the inside, running HP-UX, DNS resolving worked just fine.

On the jumphost it didn’t work at all.

Took me hours to figure out what was going on. I went over the firewall again and again. On both the jumphost and the DNS server. I went over the bind configuration again and again. The network setup. To no avail. All i got was

Got recursion not available from 192.168.1.79, trying next server

In the end it turned out to be due to the fact that on the linux jump server, I had a two nameserver lines

domain zensonic.dk
search zensonic.dk
nameserver 192.168.1.79
nameserver 192.168.1.80

I hadn’t bothered to setup the DNS at 192.168.1.80 and thus my linux client would not function. As soon as I removed 192.168.1.80 from /etc/resolv.conf everything was as it should be. I hope that you, reading this, saves some hours worth of debugging. If you do, drop me a line/mail/beer :-)

Utilizing Seagate 7200.12 drives in an MSA20

Wednesday, February 2nd, 2011

About a year ago, I upgraded an MSA20 with non-HP drives. 1TB drives (7200.11 series) made by Seagate to be precise. Here one year later, the first drives start to fail. Looking for replacements we had a hard time finding the 7200.11 series drives. We then bought some 1TB 7200.12 drives.

And they work just fine……

Same model number, just different firmware as seen from the MSA20 (CC46 vs CC38):

physicaldrive 1:7
Box: 1
Bay: 7
Status: OK
Drive Type: Data Drive
Interface Type: SATA
Size: 1000.2 GB
Firmware Revision: CC46
Serial Number:             9VPB04V3
Model: Seagate ST31000528AS
SATA NCQ Capable: False

physicaldrive 1:8
Box: 1
Bay: 8
Status: OK
Drive Type: Data Drive
Interface Type: SATA
Size: 1000.2 GB
Firmware Revision: CC38
Serial Number:             9VP4D1F1
Model: Seagate ST31000528AS
SATA NCQ Capable: False