query about EDNS UDP Packet

[Sten Carlsen]

It means that something in your path limits packet size. That could
likely be a firewall or router with a "helpful" function to pass DNS
packets on; only it thinks that a DNS packet can only be 512 bytes long.

On 31/12/12 10:49, Gaurav Kansal wrote:
>
> Hello Team,
>
>  
>
> I am getting too many entries for reducing the EDNS Packet size to 512
> bytes in my log file.
>
> For Eg:
>
>  
>
> Dec 31 03:07:20 IPv6-DNS named[3769]: success resolving
> 'dns1.vps.net/A' (in 'vps.net'?) after reducing the advertised EDNS
> UDP packet size to 512 octets
>
> Dec 31 03:07:21 IPv6-DNS named[3769]: success resolving
> 'ad.metanetwork.com/A' (in 'metanetwork.com'?) after reducing the
> advertised EDNS UDP packet size to 512 octets
>
> Dec 31 03:07:25 IPv6-DNS named[3769]: success resolving
> 'geo.admetanetwork.com/A' (in 'admetanetwork.com'?) after reducing the
> advertised EDNS UDP packet size to 512 octets
>
> Dec 31 03:07:31 IPv6-DNS named[3769]: success resolving
> 'tomcat.apache.org/A' (in 'apache.org'?) after reducing the advertised
> EDNS UDP packet size to 512 octets
>
> Dec 31 03:07:31 IPv6-DNS named[3769]: success resolving
> 'www.apache.org/A' (in 'apache.org'?) after reducing the advertised
> EDNS UDP packet size to 512 octets
>
> Dec 31 03:07:31 IPv6-DNS named[3769]: success resolving
> 'issues.apache.org/A' (in 'apache.org'?) after reducing the advertised
> EDNS UDP packet size to 512 octets
>
> Dec 31 03:07:34 IPv6-DNS named[3769]: success resolving
> 'ns1.zurich.surf.net/A' (in 'surf.net'?) after reducing the advertised
> EDNS UDP packet size to 512 octets
>
> Dec 31 03:07:34 IPv6-DNS named[3769]: success resolving
> 'ns2.surfnet.nl/AAAA' (in 'surfnet.nl'?) after reducing the advertised
> EDNS UDP packet size to 512 octets
>
> Dec 31 03:07:34 IPv6-DNS named[3769]: success resolving
> 'ns2.surfnet.nl/A' (in 'surfnet.nl'?) after reducing the advertised
> EDNS UDP packet size to 512 octets
>
> Dec 31 03:07:34 IPv6-DNS named[3769]: success resolving
> 'ns1.zurich.surf.net/AAAA' (in 'surf.net'?) after reducing the
> advertised EDNS UDP packet size to 512 octets
>
> Dec 31 03:07:34 IPv6-DNS named[3769]: success resolving './NS' (in
> '.'?) after reducing the advertised EDNS UDP packet size to 512 octets
>
> Dec 31 03:07:40 IPv6-DNS named[3769]: success resolving
> 'ns1.zurich.surf.net/A' (in 'surf.net'?) after reducing the advertised
> EDNS UDP packet size to 512 octets
>
> Dec 31 03:07:40 IPv6-DNS named[3769]: success resolving
> 'ns1.zurich.surf.net/AAAA' (in 'surf.net'?) after reducing the
> advertised EDNS UDP packet size to 512 octets
>
>  
>
> On googling for this, I got to know that this come when remote DNS
> Server doesn't support EDNS0 (i.e., packet size upto 4096 bytes).
>
>  
>
> Now I want to know whether my DNS Server supports EDNS0 for incoming
> request or not.
>
> I use the '*OARC's DNS Reply Size Test Server' *for the same and I got
> the below mentioned O/P:
>
>  
>
> #dig +short rs.dns-oarc.net txt
>
> rst.x476.rs.dns-oarc.net.
>
> rst.x450.x476.rs.dns-oarc.net.
>
> rst.x490.x450.x476.rs.dns-oarc.net.
>
> "Tested at 2012-12-31 09:40:11 UTC"
>
> "164.100.1.206 sent EDNS buffer size 4096"
>
> "164.100.1.206 DNS reply size limit is at least 490"
>
>  
>
> Does this mean that my server is not supporting EDNS0 ???
>
>  
>
>  
>
> Thanks and Regards,
>
> Gaurav Kansal
>
> Mob -- 9910118448
>
>  
>
> Happy New Year 2013.
>
> IPv4 is Over,
>
> Are your ready for new Network.
>
>  
>
>
>
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-- 
Best regards

Sten Carlsen

No improvements come from shouting:
       "MALE BOVINE MANURE!!!"

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