Root and Forwarders Servers

[Mark.Andrews at nominum.com]

	The following bug is biting you.  From the 8.2.3 change list.

 910.   [bug]           address-sorting logic was exiting early.

	In src/bin/named/ns_forw.c: nslookup change

        if (n > 1) {
                qsort((char *)qp->q_addr, n, sizeof(struct qserv),
                      (int (*)(const void *, const void *))qcomp);
        }

	to

        /* Just sort the NS RR's we added, since the forwarders may
         * be ahead of us (naddr > 0)
         */
        if (n > naddr) {
                qsort((char *)(qp->q_addr+naddr), n-naddr, sizeof(struct qserv),
                      (int (*)(const void *, const void *))qcomp);
        }

	This will work around the problem in qcomp.

	Mark


> 
> Hi there, 
> 
>  I've just installed new version of BIND (Version = named 8.2.2-P5)
> instead of good old 4.9.7 at one of my servers and now doing some testing.
> So, I'd be thankfull if anybody could clarify some nuances of
> "forwarders" option:
> 
> 0) I set "forwarders first" and "forwarders server" option and have 
>    default root.cache file.
> 
> 1) When answering a query, named first tries all(?) root servers, 	
>    and only after this tries my "forwarders server" 193.193.193.100.
>    This significantly slows dns responces.
>   
>    The problem is that I expect named to query "forwarders server"
>    first, not one of the root servers, because my forwarder answers much
>    faster than root does.  Nevertheless, I dont want to use 
>    "forwarders only " option, cause this will disable use of root servers
>    even if my "forwarder" is unavailable.
> 
> 
> Some debug 1 output from named.run (with no connection to root servers):
> 
> datagram from [client.ip].1266, fd 20, len 31
> req: nlookup(www.digex.net) id 1475 type=1 class=1
> req: found 'www.digex.net' as 'net' (cname=0)
> forw: forw -> [205.188.185.18].53 ds=4 nsid=61164 id=1475 16ms retry 4sec
> resend(addr=1 n=0) -> [195.8.99.11].53 ds=4 nsid=61164 id=1475 64ms
> resend(addr=2 n=0) -> [198.41.0.21].53 ds=4 nsid=61164 id=1475 93ms
> resend(addr=3 n=0) -> [198.41.3.38].53 ds=4 nsid=61164 id=1475 99ms
> resend(addr=4 n=0) -> [198.17.208.67].53 ds=4 nsid=61164 id=1475 118ms
> resend(addr=5 n=0) -> [192.5.5.241].53 ds=4 nsid=61164 id=1475 118ms
> resend(addr=6 n=0) -> [210.176.152.18].53 ds=4 nsid=61164 id=1475 252ms
> resend(addr=7 n=0) -> [198.41.0.4].53 ds=4 nsid=61164 id=1475 451ms
> resend(addr=8 n=0) -> [216.33.75.82].53 ds=4 nsid=61164 id=1475 971ms
> resend(addr=9 n=0) -> [192.112.36.4].53 ds=4 nsid=61164 id=1475 1006ms
> resend(addr=10 n=0) -> [192.36.144.253].53 ds=4 nsid=61164 id=1475 1419ms
> reforw(addr=11 n=0) -> [193.193.193.100].53 ds=4 nsid=61164 id=1475 -1ms
> 			^^^^^^^^^^^^^^^^^
> 
> resend(addr=12 n=0) -> [192.203.230.10].53 ds=4 nsid=61164 id=1475 2697ms
> resend(addr=0 n=1) -> [205.188.185.18].53 ds=4 nsid=61164 id=1475 16ms
> resend(addr=1 n=1) -> [195.8.99.11].53 ds=4 nsid=61164 id=1475 64ms
> datagram from [193.193.193.100].53, fd 4, len 123
> 		^^^^^^^^^^^^^^^^
> send_msg -> [client.ip].1266 (UDP 20) id=1475
> 
> 
> BR, 
> 
> Bernt
> 
> 
> 
> 
> 
--
Mark Andrews, Nominum Inc.
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at nominum.com