Friends... I am having delivery delayed isues on DNS .. i have static public IP for my domain and reverse DNS and other records like TXT/SRV is in place. but then since yesterday i am having delivery delayed to some domains and error is " 451 4.4.0 Primary target IP address responded with: "421 4.4.2 Connection dropped." so to be true i was not able to understand how to sort this out as this was only happening with few domains and as always when problem comes it bcomes critical for client.. same happened .. the domains which were giving this errors are super critical for client and i dont have much answers to this that where is the problem.. is some one please guide me here...
but then i thought of changing my delivery to SMART HOST and point it via my ISP. but i am not sure if i have done the right thing as i am not able to understand much on this. like pros & cons attached to SmartHost... why people dont use it much ... any chances of my IP getting black listed or SPAMMING ... so please guide if i kep it on smart host or how can i trouble shoot my DNS delivery issue.
Thanks
Happiness Always
Jatin