[Devel] Blacklist and failover

[Bogdan-Andrei Iancu]

Hi Alex,

Alex wrote:
> Hello, 
>
>   
>> the 408 timeout was locally generated by openser or was received? if it 
>> is the first case, was there any provisional reply received from UAS?
>>     
>
> Locally generated by server. It was first try to send packet to another server which was off-line. 
> Another requests were not sent and 477 was returned by server.
>   
yes - this is a typical case of DNS-based server - your openser detected 
the destination server as non-responsive and blocked all requests to if 
for the short period of time (4 minutes) - this a self protection 
mechanism to avoid bottlenecks and DOS against unreachable destinations.

regards,
bogdan
>   
>> I'm asking because a local generated 408 timeout with no reply received 
>> is considered a failure that triggers DNS-based failover (RFC3262) and 
>> if disable_dns_blacklist=no, the destination IP address will be 
>> blacklisted for 4 minutes.
>>
>> can you check if this was the case?
>>
>> you can inspect the content of the blacklist via MI command 
>> "list_blacklists"
>>     
>
> 200 OK
> List:: dns owner=17 flags=6
> 	Rule::  flags=0
> 		IP:: ip
> 		Mask:: 255.255.255.255
> 		Proto:: 1
> 		Port:: port
> 		Expire:: 556
>
>