RE: strange traffic on UDP port 53

From: Greg A. Woods (woodsat_private)
Date: Mon Jun 09 2003 - 09:57:11 PDT

  • Next message: Ryan Yagatich: "Re: Odd windows ICMP... any ideas what this is?"

    [ On Friday, June 6, 2003 at 10:35:34 (-0700), David Gillett wrote: ]
    > Subject: RE: strange traffic on UDP port 53
    >
    >   Replies to DNS queries should be coming FROM port 53,
    
    True, though unfortunately it's not always the case.
    
    > not
    > (necessarily) addressed TO port 53.
    
    If DNS queries are not addressed to port#53 then they're not going to
    reach any valid nameserver.
    
    (There's no standard in the DNS for specifying any alternate port for a
    nameserver so it's pretty much impossible to see normal standard DNS
    queries from random remote DNS clients on anything but port#53.  It may
    be possible to specify an alternate port in some stub resolvers, but
    then the person responsible for the nameserver they are directed at will
    know in advance what port to expect to see queries come in on.)
    
    -- 
    								Greg A. Woods
    
    +1 416 218-0098;            <g.a.woodsat_private>;           <woodsat_private>
    Planix, Inc. <woodsat_private>; VE3TCP; Secrets of the Weird <woodsat_private>
    
    ----------------------------------------------------------------------------
    ----------------------------------------------------------------------------
    



    This archive was generated by hypermail 2b30 : Tue Jun 10 2003 - 13:10:26 PDT