Les Mikesell wrote:
> carlopmart wrote:
>> Lars Hecking wrote:
>>>> options {
>>>> directory "/var/named";
>>>> dump-file "/var/named/data/cache_dump.db";
>>>> statistics-file "/var/named/data/named_stats.txt";
>>>> memstatistics-file "/var/named/data/named_mem_stats.txt";
>>>> listen-on port 53 { 127.0.0.1; 172.25.50.10; };
>>>> version "DNS Server v2.0";
>>>> dnssec-enable no;
>>>> query-source port 53;
>>>> forwarders { 208.67.220.220; 208.67.222.222; };
>>>> };
>>>
>>>> As you can see, I need to use "query-source port" param too with forwarders to
>>>> resolv names (and this is really really ugly).
>>>
>>> Explicit query-source port breaks port randomisation and is highly insecure.
>>> Your problem may be an incorrectly configured firewall that only accepts
>>> outgoing queries originating from source port 53 - it needs to accept all
>>> outgoing queries for destination port 53.
>>>
>>>
>> Thanks lars. Correctly, firewall could be the problem, but it isn't. Because
>> Ubuntu and Windows 2003/2008 doesn't have problems with it ... and resolves
>> perfectly ... And I don't have configured this firewall to accept dns queries
>> originating from source port 53 ...
>>
>
> What does 'dig' show about your access to the root servers without
> forwarders and with and without forcing the query-source port? Compare
> it to the Ubuntu system. Maybe there's something wrong with the root
> hints file - or maybe your border firewall is blocking all udp to this
> box but permitting it to the DNS servers that work.
>
Thanks Les, but I have checked it before post this problem. Ubuntu and CentOS
have the same file to do querys to root servers ...
I have find a temporary solution: reduce the MTU on CentOS server (1440) ...I
need to investigate why centOS loses some packages and ubuntu doesn't ....
--
CL Martinez
carlopmart {at} gmail {d0t} com