ISP inbound failover without BGP

Tue Mar 4 02:31:56 UTC 2014

Depending on their business, using dynamic DNS providers could be a really bad idea. If they deal only with home users who won't even know, it'll probably work. If their customers are security-aware businesses, they probably block all sites hosted with dynamic DNS systems.

Ray

> Subject: Re: ISP inbound failover without BGP
> From: matthew at corp.crocker.com
> Date: Mon, 3 Mar 2014 20:50:26 -0500
> To: elouie at yahoo.com
> CC: nanog at nanog.org
> 
> 
> 
> Depends on the application,  
> 
> SIP, VPN, SMTP, etc just setup both IPs and let the end-user application figure it out (SIP-UA register to both IPs for example)
> 
> HTTP/HTTPS setup a proxy server in a colo that is multi-homed to frontend the requests. Then it can load balance traffic over both IPs.
> 
> DNS TTL ‘tricks’ are just that, they work ‘kinda’
> 
> Fatpipe?   Crazy expensive IMHO but I hear they work ok.
> 
> -Matt
> 
> --
> Matthew S. Crocker
> President
> Crocker Communications, Inc.
> PO BOX 710
> Greenfield, MA 01302-0710
> 
> E: matthew at crocker.com
> P: (413) 746-2760
> F: (413) 746-3704
> W: http://www.crocker.com
> 
> 
> 
> On Mar 3, 2014, at 8:11 PM, Eric A Louie <elouie at yahoo.com> wrote:
> 
> > This may sound like dumb question, but... I'm used to asking those.
> > 
> > Here's the scenario
> > 
> > Another ISP, say AT&T, is the primary ISP for a customer.
> > 
> > Customer has publicly accessible servers in their office, using the AT&T address space.
> > 
> > I am the customer's secondary ISP.
> > 
> > Now, if AT&T link fails, I can provide the customer outbound Internet access fairly easily.  So they can surf and get to the Internet.
> > 
> > What about the publicly accessible servers that have AT&T addresses, though?
> > 
> > One thought I had was having them use Dynamic DNS service.  
> > 
> > Are there any other solutions, short of using BGP multihoming and having them try to get their own ASN and IPv4 /24 block?
> > 
> > 
> > It looks like a few router manufacturers have devices that might work, but it looks like a short DNS TTL (or Dynamic DNS) needs to be set so when the primary ISP fails, the secondary ISP address is advertised.
> > 
> 
> 