Ascend Archive
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Re: (ASCEND) DNS resolution bug


 Maybe I'm a little confused, but I thought this was only a problem when
doing resolution for that NAS not from a ppp connection to the NAS??

Jason Nealis
Director Internet Operations / Network Access
Erols Internet (An RCN Company)


On Mon, 11 May 1998, Jesse Martinez wrote:

> So what is Ascend going to do about this. I'm getting IRC users that can't
> get to certain servers because of this.
> 
> 
> -Jesse Martinez-
> CEO
> East County Internet Services, Inc.
> Voice (925)706-4280
> Fax (925)706-4282
> On Mon, 11 May 1998, Kevin A. Smith wrote:
> 
> > At 09:27 AM 5/8/98 -0700, Kit Knox wrote:
> > >
> > >There appears to be a problem with Ascend's DNS resolution code and hosts
> > >with many A records.  Could people with a minute to spare please do the
> > >following : 
> > >
> > >1.  Telnet to any Ascend router.
> > >2.  Enter term serv mode.
> > >3.  Attempt to ping/traceroute to  www.microsoft.com.
> > >4.  Record if the DNS lookup fails.
> > >5.  Let me know which nameserver you are using and what version of Bind it
> > >is running.
> > 
> > The problem is an old one that has just surfaced on our products. It's
> > been around as Kit observes on other (including UNIX) platforms for a
> > while. It relates to a section of the relevant RFC - where DNS replies
> > of over 512 bytes is addressed.
> > 
> > Conclusion so far...
> > 
> > DNS is normally a UDP based protocol, however if the reply is longer than
> > 512 bytes, the RFC recommends establishing a TCP connection.  This is not a
> > widely implemented portion of the RFC, as few DNS lookups require more than
> > 512 byte responses.  
> > 
> > We have considered processing what we could (the first 512 bytes) and
> > ignoring the TC bit.  But that could have unpredictable consequences.
> > The alternative is also unpredictable, since virtually no one else supports 
> > the TCP option, even if we did, it most likely wouldn't work.
> > 
> > 
> > Kevin 
> > ++ Ascend Users Mailing List ++
> > To unsubscribe:	send unsubscribe to ascend-users-request@bungi.com
> > To get FAQ'd:	<http://www.nealis.net/ascend/faq>
> > 
> 
> ++ Ascend Users Mailing List ++
> To unsubscribe:	send unsubscribe to ascend-users-request@bungi.com
> To get FAQ'd:	<http://www.nealis.net/ascend/faq>
> 

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References: