How does your firewall handle DNS messages > 512 octets?

[Dave Piscitello <dave () corecom com>]

Hi all,

I am trying to understand how different firewalls behave when they 
receive a UDP datagram containing a DNS message that uses EDNS0 (RFC 
2671) to support message sizes greater than the 512 maximum specified in 
RFC 1035 (original DNS).

Specifically,

- does your firewall block/silently discard such messages by default?
- do you know the command to allow the message if blocked by default?

I've found dozens of claims that firewalls don't handle EDNS0 correctly, 
but after a long search, I've only found URLs indicating that Firewall-1 
and Pix block by default and have workarounds.

I'm curious whether SonicWall, Netscreen, Symantec, etc. behave 
similarly. I'd also be curious to learn the behavior of IPS devices and 
DNS proxies (Watchguard, WinProxy, etc).

You can send replies directly to me and I'll compile responses and post 
to the list to save electrons.

Thanks in advance,

Dave

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