Name Resolution issue with one domain

Matus UHLAR - fantomas uhlar at fantomas.sk
Thu Mar 22 09:46:12 UTC 2012


>On 21/03/2012 09:41, Matus UHLAR - fantomas wrote:
>> maybe the admin set that up to force local servers using random ports,
>> instead of 53, for outgoing requests. Nobody should use port 53 for
>> _ougtoing_ requests.

On 21.03.12 23:41, Anand Buddhdev wrote:
>You're wrong. A name server can use any source port from 1 up to 65535
>for an outgoing query, as long as that port is not in use by any other
>process on the system.

well, it _can_ but because ports < 1024 are undesrtood as privileged, 
it should not use them.

>In fact, up until Kaminsky's revelation, many BIND servers used a fixed
>source port of 53.

yes, but because of Kaminsky's revelation, servers should not use that 
port anymore.

While it's of up to the the admin of resolving server, it's possible 
that FW admin at dubai airport had reason to block ports>1024. 

Maybe they got attack from enabled chargen or echo UDP services from 
somewhere. We do not knot that. But we surely know that OP's 
nameservers use port 53 which they should not use...


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Matus UHLAR - fantomas, uhlar at fantomas.sk ; http://www.fantomas.sk/
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