queer dns access problem

Bill Tangren bjt at usno.navy.mil
Wed Dec 12 21:30:19 UTC 2007


> Bill Tangren wrote:
>>>> -----Original Message-----
>>> Some ideas:
>>>
>>> Turn off firewalling if possible.
>>>
>>> Check default route
>>> # ip route list
>>> 10.212.166.0/24 dev eth0  proto kernel  scope link  src 10.212.166.26
>>> 169.254.0.0/16 dev eth0  scope link
>>> default via 10.212.166.1 dev eth0 <----!!!!
>>>
>>> correct if necessary.
>>>
>>> Check for UDP connectivity
>>>
>>> # nmap -PU -p53 DNS.SERVER.IP.ADDRESS
>>>
>>> # traceroute -U DNS.SERVER.IP.ADDRESS
>>
>>
>> OK, this is what is produced on the server that works:
>>
>> *****
>> [root at mach2 X11]# ip route list
>> 169.254.0.0/16 dev eth0  scope link
>> 10.0.0.0/8 dev eth0  proto kernel  scope link  src 10.1.5.58
>> default via 10.1.1.2 dev eth0
>
> So mach2:eth0 has an IP of 10.1.5.58, right?


Correct.


>
>> [root at mach2 ~]# nmap -PU -p53 10.1.1.6
>> Starting nmap 3.70 ( http://www.insecure.org/nmap/ ) at 2007-12-12 15:33
>> EST
>> Note: Host seems down. If it is really up, but blocking our ping probes,
>> try -P0
>> Nmap run completed -- 1 IP address (0 hosts up) scanned in 2.054 seconds
>>
>> [root at mach2 ~]# nmap -PU -p53 10.1.1.46
>> Starting nmap 3.70 ( http://www.insecure.org/nmap/ ) at 2007-12-12 15:33
>> EST
>> Interesting ports on aurora.timenet.usno.navy.mil (10.1.1.46):
>> PORT   STATE SERVICE
>> 53/tcp open  domain
>> MAC Address: 00:18:8B:38:28:97 (Unknown)
>>
>> Nmap run completed -- 1 IP address (1 host up) scanned in 0.295 seconds
>>
>> [root at mach2 ~]#
>> *****
>>
>> The server that doesn't looks like this:
>>
>> *****
>> [root at aa-cvs ~]# ip route list
>> 169.254.0.0/16 dev eth0  scope link
>> 10.0.0.0/8 dev eth0  proto kernel  scope link  src 10.1.5.58
>> default via 10.1.1.2 dev eth0
>
> and aa-cvs:eth0 also has an IP address of 10.1.5.58, right?
>
> See the problem yet?  Same IP address on two nodes?


Sorry. That's a cut and paste error. It is actually 10.1.5.94. I just
rechecked.





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