E-mail failover to back up Internet connection

From: Todd (Todd_at_discussions.microsoft.com)
Date: 02/19/05 

Date: Sat, 19 Feb 2005 11:39:02 -0800

I’m trying to determine how to ensure in/outbound e-mail will flow over our
backup Internet connection if the primary Internet connection fails.

We have firewall/router device in front of our SBS 2003 box. The device has
two WAN interfaces. WAN1 has an IP from our primary ISP (ISP1) and WAN2 has
an IP from ISP2.

Our DNS records, hosted by a third company, has an A record setup to match
the IP from ISP1 to the host name of our SBS box (ie sbs.ourdomain.com). The
hosting company has told me that setting up a second A record the matches the
IP from ISP2 to the same host name (sbs.ourdomain.com) will not work.

A consultant has told me in order to accomplish our email failover goal, we
would need to host DNS ourselves so that our sever has the authoritative DNS
record. He is saying that our failover will not work if the receiving
mailserver uses reverse DNS checks. He says once we are hosting our own DNS
we can run inexpensive software that will monitor our dual internet
connections and make the appropriate DNS changes if the connection to ISP1
fails. It seems there is a consensus that hosting our own DNS in an SBS
environment is not advisable. Is this true?

How do we configure everything so that inbound and outbound e-mail will work
on our connection to ISP2 if the connection to ISP1 fails?

Thanks

-Todd

Relevant Pages

  • RE: svchost.exe Application Error.
    ... P.S the NetBio over TCP/IP is on the Internet Protocol TCP/IP properties, ... you gone to the Network connection and Right click your Wireless/Wired LAN, ... the IP address and the DNS server address are given by the ... internet connection provider. ...
    (microsoft.public.windowsxp.network_web)
  • Re: Is there something very simple wrong here?
    ... Dns domain name is not specified. ... The redir is bound to 1 NetBt transport. ... so right click and disable that connection. ... > check the box for Internet Connection Firewall to protect your ...
    (microsoft.public.windowsxp.network_web)
  • Re: Telnet sessions "freezing"
    ... > the rest of the world) by trying a telnet to the local host loop back. ... > If that fails during the connection, check the DNS, if it fails after ... > the connection is established, its got to be in the local software. ... DNS is working. ...
    (comp.sys.hp.hpux)
  • DNS Multihomed timeout
    ... one for our Internet Connection: ... WIth the INet connection turn off, ... It forwards all requests not for the local network to the ISP DNS server. ... With the connection turned on our DNS times out when looking for a address outside of our network. ...
    (microsoft.public.win2000.dns)
  • Re: DNS address
    ... Doug Sherman wrote: ... I got the message that the connection was broken. ... >>in the DNS address but didn`t know what that was so I tried without any. ... >>That setup gave me back the internet connection ...
    (microsoft.public.windowsxp.network_web)