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Differences between version 20 and predecessor to the previous major change of NamedNotes.

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Newer page: version 20 Last edited on Thursday, November 11, 2004 4:01:22 pm by AristotlePagaltzis Revert
Older page: version 13 Last edited on Wednesday, February 11, 2004 4:54:29 pm by DrewBroadley Revert
@@ -1,5 +1,5 @@
-See Also: named(8), named.conf(5), [HowToChrootBINDHOWTO] , [DNSHowTo], ZoneFile.  
+See Also: named(8), named.conf(5), [DNSHowTo], ZoneFile, [DNSBestPractices]  
 ---- 
 If you have problems with your zone files, you probably forgot a "." 
  
 ---- 
@@ -7,15 +7,14 @@
  
  $GENERATE 150-250 $.0.0.10.in-addr.arpa. PTR dhcp-$.example.com. 
  
 ---- 
-Remember, MX's and NS records can't point to CNAMEs. 
+Remember, MX's and NS records can't point to CNAMEs or directly to raw IP addresses, point them to something with an A or AAAA (or A6) record
  
 ---- 
-An MX record should not be a raw IP address either
+You can have more than one record type for a domain/host, so long as none of them as CNAMEs. ie: you can have two A's, or an A and a TXT, but ''never'' an A and a CNAME, or an TXT and a CNAME, or even two CNAMES
  
-----  
-You can have more than one record type for a domain/host, so long as none of them as CNAMEs. ie: you can have two A's, or an A and a TXT, but ''never'' an A and a CNAME , or an TXT and a CNAME, or even two CNAMES
+The same applies to DNAME's ( you can't have a DNAME and any other record type , including another DNAME or CNAME)
  
 ---- 
 You can define seperate TTL's (in seconds) for records e.g.: 
  shortttl 3600 IN A 127.0.0.1 
@@ -77,4 +76,32 @@
  
 You can find more details about the patch at the URL below. 
  http://www.isc.org/products/BIND/delegation-only.html 
 ---- 
+I've written a [script|WLUG:/archive/validate_zones] to check for obvious mistakes in zone files (forgotten a "." or forgotten to update the serial).  
+----  
+  
+In named.conf in Debian woody there is this comment:  
+  
+options {  
+ directory "/var/cache/bind";  
+  
+ // If there is a firewall between you and nameservers you want  
+ // to talk to, you might need to uncomment the query-source  
+ // directive below. Previous versions of BIND always asked  
+ // questions using port 53, but BIND 8.1 and later use an unprivileged  
+ // port by default.  
+  
+ //query-source address * port 53;  
+...  
+}  
+  
+I found that when using the standard ipmasq scripts ( in /usr/share/doc/ipmasq/examples/stronger ) to create a firewall then, despite what the comment says that uncommenting that line caused dns lookups to stop working, ie the firewall blocked them from going out.  
+----  
+If you run nscd (if you don't know, you probably are...) and running named on the same machine then you should disable nscd's use of DNS, edit /etc/nscd.conf and put:  
+ enable-service hosts off  
+If the link to your DNS server is slow enough (or unreliable enough) that you do want some caching, turning the times down on nscd's caching helps solve a lot of weird issues  
+ positive-time-to-live hosts 60  
+ negative-time-to-live hosts 10  
+causes it to cache successful responses for 60s and failed responses for 10 seconds. This means that when you look something up it will be cached for a short time and then immediately flushed from the cache rather than nscd's habit of caching bad data.  
+  
+nscd also believes that hosts are a symmetric relationship. Thus if "4.3.2.1.in-addr.arpa." resolves to "localhost" then localhost must resolve to "1.2.3.4". Imagine not only the fun you have trying to diagnose these issues, but the potential for evildoers to screw with your security.