Re: dnscache and oversized answers

On Mon, Oct 06, 2008 at 10:55:12 -0000, John Levine wrote:
> One of my users noticed that MX lookups for xo.net were timing out.
> The problem turns out to be that XO's name servers are putting in too
> many additional section records and are returning oversized answers of
> about 540 bytes, which dnscache then throws away.

Try this.

--- dns_transmit.c~	2008-01-09 00:50:09.559806518 +0200
+++ dns_transmit.c	2008-10-06 14:16:28.539802762 +0300
@@ -352,7 +352,7 @@ have sent query to curserver on UDP sock
       if (errno == error_connrefused) if (d->udploop == 2) return 0;
       return nextudp(d);
     }
-    if (r + 1 > sizeof udpbuf) return 0;
+    if (r + 1 > sizeof udpbuf) return firsttcp(d);
 
     if (irrelevant(d,udpbuf,r)) return 0;
     if (serverwantstcp(udpbuf,r)) return firsttcp(d);

--

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