From: Kris Emmett (kris@sentryworx.com)
Date: Mon Mar 01 2004 - 12:20:06 GMT-3
You can use something like ultradns.com.
Changing host records on the fly works fine.
For mail Chucks solution works fine.
Kris
9401
-----Original Message-----
From: Church, Chuck [mailto:cchurch@wamnetgov.com]
Sent: Monday, March 01, 2004 8:52 AM
To: Alex Hsieh; CCIE R&S Mailing list
Subject: RE: Wan link backup
I think what you're saying is having two different DNS servers valid,
one on each network block. These two are both registered with Network
Solutions (or whatever they're calling themselves these days). One as a
primary, and one as a secondary. So if the DS3 goes down, the primary
is now unreachable and the secondary would become active, giving out
addresses valid on the backup link, whereas the primary DNS was giving
out addresses valid on the DS3 block. The problem would be caching of
DNS records. You're TTL for the nameservers would have to be extremely
low for this to work, and probably not a good solution. I'm not sure if
NetSol would even accept a TTL of just minutes for an NS record. The
incoming mail problem is easily solved with multiple MX records. For
incoming HTTP, you might want to talk to a hosting company that can
redirect your WWW records to different hosts. No luck with static
routes from the ISP?
Chuck Church
Lead Design Engineer
CCIE #8776, MCNE, MCSE
Wam!Net Government Services
13665 Dulles Technology Dr. Ste 250
Herndon, VA 20171
Office: 703-480-2569
Cell: 703-819-3495
cchurch@wamnetgov.com
PGP key:
http://pgp.mit.edu:11371/pks/lookup?op=index&search=cchurch%40wamnetgov.
com
> -----Original Message-----
> From: Alex Hsieh [mailto:ccie21@hotmail.com]
> Sent: Sunday, February 29, 2004 10:58 PM
> To: CCIE R&S Mailing list
> Subject: Re: Wan link backup
>
>
> What if I setup one DNS server for each link,and register
> DNS record with both of my DNS server address.Will it work? Thanks.
>
> regards
> Alex
> ----- Original Message -----
> From: "Church, Chuck" <cchurch@wamnetgov.com>
> Cc: "CCIE R&S Mailing list" <ccielab@groupstudy.com>
> Sent: Sunday, February 29, 2004 5:51 AM
> Subject: RE: Wan link backup
>
>
> > Whoops. Should have read it more carefully. BGP shouldn't
> be needed, but
> you'll need some cooperation from the ISP. Since it's
> asymmetric DSL, it
> looks like it may have been provisioned by their 'home' DSL
> group, vs. the
> 'business' DSL group. Getting the 'home' group to coordinate
> routing with
> the leased circuit group may be tough. All depends on the
> ISP. I tried
> doing a network like this with Verizon a few years ago. It
> was like pulling
> teeth. Eventually gave up and did something else...
> >
> > Chuck Church
> > Lead Design Engineer
> > CCIE #8776, MCNE, MCSE
> > Wam!Net Government Services
> > 13665 Dulles Technology Dr. Ste 250
> > Herndon, VA 20171
> > Office: 703-480-2569
> > Cell: 703-819-3495
> > cchurch@wamnetgov.com
> > PGP key:
> http://pgp.mit.edu:11371/pks/lookup?op=index&search=cchurch%40
> wamnetgov.com
> >
> > > -----Original Message-----
> > > From: Scott, Tyson C [mailto:tyson.scott@hp.com]
> > > Sent: Saturday, February 28, 2004 1:15 PM
> > > To: Jay Hennigan; Church, Chuck
> > > Cc: Alex Hsieh; CCIE R&S Mailing list
> > > Subject: RE: Wan link backup
> > >
> > >
> > > Yes, your issue is with the ISP. You need to work with them so
> > > they are advertising your network back over the ADSL, however you
> > > want them to do
> > > it.
> > >
> > > Regards,
> > >
> > > Tyson Scott
> > > Agilent Problem Management Team
> > > Managed Network Services
> > > Phone: 313-583-5812
> > > Pager: 877-997-0811
> > >
> > >
> > > -----Original Message-----
> > > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
> > > Behalf Of Jay Hennigan
> > > Sent: Saturday, February 28, 2004 12:38 AM
> > > To: Church, Chuck
> > > Cc: Alex Hsieh; CCIE R&S Mailing list
> > > Subject: RE: Wan link backup
> > >
> > > On Fri, 27 Feb 2004, Church, Chuck wrote:
> > >
> > > > The inbound HTTP would be tough to fix without BGP.
> Mail is easy
> > > > though. Create another MX record with a lower priority
> pointing to
> > > > an address valid on the DSL link. On the other hand,
> you've got a
> > > > router that can certainly handle BGP. Might be a
> better solution...
> > >
> > > I don't see where BGP would be needed here as both links
> are from the
> > > same ISP. A dynamic routing protocol such as OSPF or
> even a simple
> > > floating static of your routed addresses over the ADSL
> link over the
> > > static on the DS-3 and a corresponding floating static
> default towards
> > > the ADSL on your end should do the trick.
> > >
> > > Either of these requires the cooperation and some clue on
> the part of
> > > your ISP, of course.
> > >
> > > We do this all the time for DSL backup of T-1 and greater.
> > >
> > > > > -----Original Message-----
> > > > > From: Alex Hsieh [mailto:ccie21@hotmail.com]
> > > > >
> > > > > Our company currently uses 3725 router with 2 wan
> > > links,one T3,
> > > > >
> > > > > the other is 1.5M ADSL.We use ADSL as backup
> connection.Both links
> > > > >
> > > > > belong to same ISP.The other day when T3 breaks,ADSL
> link come up.
> > > > >
> > > > > Outbound connection works,but outside can't establish inbound
> > > > > connection
> > > > >
> > > > > to our server (mail,www).Is there anyway to enable inbound
> > > > > server connection
> > > > >
> > > > > other than using BGP or other load-balancing device?Thanks.
> > >
> > > --
> > > Jay Hennigan - CCIE #7880 - Network Administration - jay@west.net
> > > WestNet: Connecting you to the planet. 805 884-6323 WB6RDV
> > > NetLojix Communications, Inc. - http://www.netlojix.com/
> > >
> > > ______________________________________________________________
> > > _________
> > > Please help support GroupStudy by purchasing your study materials
> > > from: http://shop.groupstudy.com
> > >
> > > Subscription information may be found at:
> > > http://www.groupstudy.com/list/CCIELab.html
> >
> >
> ______________________________________________________________
> _________
> > Please help support GroupStudy by purchasing your study
> materials from:
> > http://shop.groupstudy.com
> >
> > Subscription information may be found at:
> > http://www.groupstudy.com/list/CCIELab.html
>
> ______________________________________________________________
> _________
> Please help support GroupStudy by purchasing your study
> materials from:
> http://shop.groupstudy.com
>
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
This archive was generated by hypermail 2.1.4 : Thu Apr 01 2004 - 08:15:11 GMT-3