|SUBJECT ||Re: [NYLXS - HANGOUT] Backup Network Services
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Date: Fri, 14 Nov 2008 07:32:26 -0500
Subject: Re: [NYLXS - HANGOUT] Backup Network Services
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Is the sender on the list? If not can you forward this to them?
The right way to do this is to have split horizon routing with BGP.
Barring, that they can have two NAT translations their facility so that
they have an internal network IP address space that is publically
accessable as either public IP A or public IP B. (I would
recommend that trick with at least a 3 port router. A a linux
box could do it)
Finally, I would suggest as the DSL is considered to be a backup.
Split the DNS requests on the Cable modem and DSL with a short time out
and have the DNS primarily give the cable modem public addresses with
the DNS having a method to update to the DSL if that line is down.
(hmm. running the DNS on that above linux box might do the trick)
Note, these are just my ideas that have not actually been tested on
a real network. Any real network professional will probably tell you
that I am wrong in so many ways.
On Thu, Nov 13, 2008 at 09:13:04PM -0500, Ruben Safir wrote:
> [QUOTE=Speedy]Got a question and I thought maybe you would know the answer.
> As you know I co-own a web hosting company and we have our internet line
> from Time Warner. We have been having outages every now and then so we
> have been looking around for something else. The problem is that we
> can't get a better service where we are located without paying a few
> times what we have now. Today we found out that we can get a line from
> Bellsouth for a low price and it would have a pretty good upload and
> download. It is a Business Class DSL. This would ONLY be used as a
> back-up to the main backbone to the server.
> How would you suggest setting that up? Both lines could be run to our
> data center of course rather than having it setup off site.
> What I would like to have happen is this---
> Server A (TW) Server B (Bellsouth)
> Server A backs up to B every night, or more often if needed---if Server
> A goes out the DNS will just push all requests over to B untill the line
> comes back on. Hopefuly without us having to change any settings at all,
> because sometimes it goes off at 2am.
> Is this possible, or can you give some ideas on what we could do?
> We are working on one day upgrading to fiber as we are located right at
> a main fiber hub and can get on it quite quickly.
> Thanks for your help.
> This is an old question but it is really a clustering issue and not a
> DNS issue.
> First, let me understand a few things. What is the reverse DNS of your
> IP address and you DO have static IP addresses. I'm sure you do.
> The quick and dirty was is to set up the DNS like google does:
> ruben-at-www2:~> dig www.google.com
> ; <<>> DiG 9.5.1b1 <<>> www.google.com
> ;; global options: printcmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 22723
> ;; flags: qr rd ra; QUERY: 1, ANSWER: 5, AUTHORITY: 7, ADDITIONAL: 0
> ;; QUESTION SECTION:
> ;www.google.com. IN A
> ;; ANSWER SECTION:
> www.google.com. 194046 IN CNAME www.l.google.com.
> www.l.google.com. 300 IN A 18.104.22.168
> www.l.google.com. 300 IN A 22.214.171.124
> www.l.google.com. 300 IN A 126.96.36.199
> www.l.google.com. 300 IN A 188.8.131.52
> ;; AUTHORITY SECTION:
> l.google.com. 24057 IN NS e.l.google.com.
> l.google.com. 24057 IN NS b.l.google.com.
> l.google.com. 24057 IN NS g.l.google.com.
> l.google.com. 24057 IN NS a.l.google.com.
> l.google.com. 24057 IN NS f.l.google.com.
> l.google.com. 24057 IN NS d.l.google.com.
> l.google.com. 24057 IN NS c.l.google.com.
> ;; Query time: 111 msec
> ;; SERVER: 184.108.40.206#53(220.127.116.11)
> ;; WHEN: Thu Nov 13 21:00:18 2008
> ;; MSG SIZE rcvd: 228
> Notice that the name www.google.com points to a canical name which
> itself has multiple IP addresses is a theoretical host. Make one host
> on the DSL line and the other on whatever line that is. Its a good idea
> to also, if not absolutely necessary, to have multiple DNS servers for
> this. if the line goes down the other DNS server has to be reachable.
> Now that leaves only an issue of load balancing, which is something more
> than I can really get into BUT, check out the NYLXS mailing list
> and folks there deal with this all the time.