Wednesday, 20 August 2014

Weirdness with DNS

So I've not yet got the bottom of this one, but I do have a work-around.

I'm trying to register my Linux box with our internal Red Hat Network server, using the rhn_register command.

Whilst trying to validate that I could connect to the server, I tried this command: -

--2014-08-20 13:34:18--  https://rhn.linux.ibm.com/pub/bootstrap/bootstrap.sh
Resolving rhn.linux.ibm.com... failed: Temporary failure in name resolution.
wget: unable to resolve host address "rhn.linux.ibm.com"


or: -


--2014-08-20 13:37:41--  https://rhn.linux.ibm.com/pub/bootstrap/bootstrap.sh
Resolving rhn.linux.ibm.com... failed: Temporary failure in name resolution.
wget: unable to resolve host address "rhn.linux.ibm.com"


However, I was able to ping the box: -


PING rhn.linux.ibm.com (9.37.253.136) 56(84) bytes of data.
64 bytes from 9.37.253.136: icmp_seq=1 ttl=128 time=589 ms
64 bytes from 9.37.253.136: icmp_seq=2 ttl=128 time=544 ms
^C
--- rhn.linux.ibm.com ping statistics ---
3 packets transmitted, 2 received, 33% packet loss, time 2175ms
rtt min/avg/max/mdev = 544.718/567.256/589.795/22.551 ms


from both the Linux guest and the Mac host: -


PING ftp3.linux.ibm.com (9.37.253.130): 56 data bytes
64 bytes from 9.37.253.130: icmp_seq=0 ttl=48 time=562.601 ms
64 bytes from 9.37.253.130: icmp_seq=1 ttl=48 time=789.634 ms
^C
--- ftp3.linux.ibm.com ping statistics ---
3 packets transmitted, 2 packets received, 33.3% packet loss
round-trip min/avg/max/stddev = 562.601/676.118/789.634/113.516 ms


Interestingly, whilst the Mac host is using my home broadband router as a DNS server: -

cat /etc/resolv.conf

#
# Mac OS X Notice
#
# This file is not used by the host name and address resolution
# or the DNS query routing mechanisms used by most processes on
# this Mac OS X system.
#
# This file is automatically generated.
#
domain home
nameserver 192.168.1.254


the Linux guest is using the Mac host: -

cat /etc/resolv.conf

# Generated by NetworkManager
domain localdomain
search localdomain uk.ibm.com
nameserver 192.168.8.2


The solution ?

I added the host to my /etc/hosts file: -

...
9.37.253.136    rhn.linux.ibm.com
...

Now it works .....

Why ?

I do not know.

I'm assuming that VMware is somehow blocking things, but I'm not quite sure .....

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