IP Tables problem

Mike Burger mburger at bubbanfriends.org
Thu Oct 21 17:45:10 UTC 2004


Interesting...wasn't aware.  Still won't convince me to open up tcp/53 to 
anyone other than my secondary DNS servers, but, then again, my zone info 
isn't so huge, per host, that it should require such a large response. <G>

On Thu, 21 Oct 2004, antonio tuozzo wrote:

> Hi Mike,
> this is an extract from Tcp/Ip Illustrated (R. Stevens)
> .....
> When the resolver issues a query and the response comes back with the TC 
> bit set ("truncated") it means the size of the response exceeded 512 
> bytes, so only the first 512 bytes were returned by the server. The 
> resolver normally issues the request again, using TCP. This allows more 
> than 512 bytes to be returned. Since TCP breaks up a stream of user data 
> into what it calls /segments,/ it can transfer any amount of user data, 
> using multiple segments.
> .....
> 
> Mike Burger wrote:
> 
> >Sure about that?  My understanding was that TCP is only used for zone file 
> >transfer type use, and UDP for queries.  I hadn't heard that there was any 
> >sort of TCP use for queries.
> >
> >On Wed, 20 Oct 2004, antonio tuozzo wrote:
> >
> >  
> >
> >>This is true! However, normal queries are single UDP requests. DNS system uses TCP only when data size replies is > 512 bytes.
> >>On Wed, Oct 20, 2004 at 06:20:20PM +0200, Crucificator wrote:
> >>    
> >>
> >>>As a matter of fact DNS uses both TCP and UDP.
> >>>
> >>>redhat-list mailing list
> >>>unsubscribe mailto:redhat-list-request at redhat.com?subject=unsubscribe
> >>>https://www.redhat.com/mailman/listinfo/redhat-list
> >>>      
> >>>
> >>    
> >>
> >
> >  
> >
> 
> 

-- 
Mike Burger
http://www.bubbanfriends.org

Visit the Dog Pound II BBS
telnet://dogpound2.citadel.org or http://dogpound2.citadel.org

To be notified of updates to the web site, visit 
http://www.bubbanfriends.org/mailman/listinfo/site-update, or send a 
message to:

site-update-request at bubbanfriends.org

with a message of: 

subscribe




More information about the redhat-list mailing list