[Dnsmasq-discuss] Two questions about the cache and how dnsmasq forwards queries

[SamLT]

> 
> So there's your problem, the TTL of the first CNAME in the chain is zero,
> 
> www.google.com.         0       IN      CNAME   www.l.google.com.>
> 
> 
> Strange, when I do the same thing (via my ISPs server) I get
> ;; ANSWER SECTION:
> www.google.com.		9620	IN	CNAME	www.l.google.com.
> www.l.google.com.	220	IN	CNAME	www-tmmdi.l.google.com.
> www-tmmdi.l.google.com.	53	IN	A	66.102.9.99
> 
> Maybe your ISPs DNS server is playing games?


> 
> A nameserver which takes less than three seconds to answer would
> solve all your problems. If that's caused by latency in the link to
> your ISP, traffic shaping will help a lot. If the problem is with
> the server (and it's messing with TTLs too), then either shout at
> your ISP or maybe use openDNS or Google's public DNS service?
> 
> 

I think my ISP also REDIRECTs DNS traffic to their nameservers, since, I
get the same result using google public dns service. (and this doesn't
happen @home with an other ISP).

Well, this is going to be... fun!

One bonus question though: how come they're able to modify the TTL of some
CNAMEs? Is that a bug or... a feature (of some software)?

The only thing I've been able to find is a message in the namedroppers ML
statuing CNAME TTL should probably be equal to DNAME TTL...
http://www.ops.ietf.org/lists/namedroppers/namedroppers.2007/msg00089.html



As an additionnal hint, when using tcp queries, I get 'normal' CNAME TTL:
	dig @66.178.2.25 www.google.com | grep CNAME
	www.google.com.         0       IN      CNAME   www.l.google.com.

	dig @66.178.2.25 www.google.com +tcp | grep CNAME
	www.google.com.         603696  IN      CNAME   www.l.google.com.

but it only works when using other nameservers than those of my ISP, so I
guess the problem is on my ISP nameservers and they only redirect udp
port 53 traffic to them. Does it sounds realistic?


I'd like to collect as much information as I can before I contact my ISP,
eventhough I think they'll just ignore me anyway...


Well, this probably doesn't belong to this ML anymore, but I send this
message anyway just in case you had some thoughts to share on the issue.

Thank you for reading, thank you Simon for your valuable help.


samlt