dns cache beyond ttl - viasat / exede

[sabri at cluecentral.net (Sabri Berisha)]

Hi Mike,

The UT uses a combination of caching, prefetching, and spoofing to accelerate web traffic for users. On the terrestrial side, there is a cluster of accelerators that also take part in that process. 

What is the "lag" time that you have observed? Also, do you know if your clients are on the Viasat-1 or Viasat-2 satellite? The infrastructure behind both satellites differs significantly.

I used to work for Viasat and have forwarded your mail to a few of my former colleagues.

Thanks, 

Sabri

----- On Oct 7, 2019, at 9:08 AM, Mike mike-nanog at tiedyenetworks.com wrote:

> Hello,
> 
> 
>Â Â Â  I am moving a number of web sites from one colo to another,
> re-numbering them in the process, and I have run into an interesting
> issue I'd like to solicit feedback on.
> 
>Â Â Â  My dns TTL's are all 300 seconds, and I have noticed that once I
> update the A records with the new addresses, most (but not all) web
> clients begin using the new address within 5 minutes or so. However,
> there is a persistent set of stragglers who continue accessing the
> site(s) on their old addresses for far in excess of this - up to a week
> in fact. And, what I have noted, all of these clients have something in
> common - they all appear to be satellite users of viasat/exede.  This is
> based on whois lookups of the ip addresses of the clients. Note, I am
> NOT expecting 'turn on a time' - just looking for clients to refresh
> within a reasonable time.
> 
>Â Â Â Â Â Â  I am wondering if perhaps this is due to some kind of (known?)
> bug in the embedded dns cache/client in the client satellite modem, or
> if there is another plausible explanation I am not seeing. It compounds
> my problem slightly since I have to continue running the web sites at
> both the old and new addresses while these things time out I guess and
> it's just inconvenient.
> 
> 
> Thanks.
> 
> 
> MIke-