On Feb 14, 2012, at 2:16 PM, Mark Andrews wrote: >> ISC's BIND has (or had) a MINTTL value of 5 minutes / 300 seconds. >> It's probably unreasonable to expect other platforms to refetch DNS >> records faster than that. > > To the best of my knowlege this is just plain wrong.
Look at BIND-4.8.3 and check named/db_update.c around line 40: int min_cache_ttl = (5*60); /* 5 minute minimum ttl */ ...and then: fixttl(dp) register struct databuf *dp; { if (dp->d_zone == 0 && !(dp->d_flags & DB_F_HINT)) { if (dp->d_ttl <= tt.tv_sec) return; else if (dp->d_ttl < tt.tv_sec+min_cache_ttl) dp->d_ttl = tt.tv_sec+min_cache_ttl; else if (dp->d_ttl > tt.tv_sec+max_cache_ttl) dp->d_ttl = tt.tv_sec+max_cache_ttl; } return; } ...or check named/ns_req.c around line 720 for the equivalent for a secondary NS: if (dp->d_ttl) ttl = dp->d_ttl; else ttl = zp->z_minimum; /* really default */ #ifdef notdef /* don't decrease ttl based on time since verification */ if (zp->z_type == Z_SECONDARY) { /* * Set ttl to value received from primary, * less time since we verified it (but never * less than a small positive value). */ ttl -= tt.tv_sec - zp->z_lastupdate; if (ttl <= 0) ttl = 120; } #endif Regards, -- -Chuck _______________________________________________ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users