Cisco ASA 5505 and EDNS issue

resolution: update your running config on your firewall. See below

issue:
I changed my primary internal DNS to run on a RHEL 6.2 system. After that there were noticeable lags occasionally when I would browse.  Upon review of the syslog I noticed messages like the following;

Jan 31 22:44:41 zion named[26381]: success resolving 'p03-bookmarks.icloud.com/A' (in 'icloud.com'?) after reducing the advertised EDNS UDP packet size to 512 octets

I happen to use a Cisco ASA 5505 and I did some digging around.

firewall(config)# show run | grep mess
  message-length maximum 512

So - it turns out the value is set as part of a policy-map.  Let's tune it.


firewall(config)# policy-map type inspect dns preset_dns_map
firewall(config-pmap)# parameters
firewall(config-pmap-p)# no message-length maximum 512
firewall(config-pmap-p)# message-length maximum 4096
firewall(config-pmap-p)# 
firewall(config-pmap-p)# write mem
Building configuration...
Cryptochecksum: 3a1cdf20 91ce7d1e d8b188fc 1ac006fb 


4215 bytes copied in 1.420 secs (4215 bytes/sec)
[OK]
firewall(config-pmap-p)# 

Everything is better... now I just get these errors (and nothing on my side will fix this issue)

Jan 31 22:46:30 zion named[26381]: error (network unreachable) resolving 'thumbnail.newsinc.com/A/IN': 2001:500:90:1::18#53