hi, i have 2003 r2 ent sp2 server. and mail server installed there. i have adsl connection to my office, and also have a static ip address which configured for this mail server. For a reserve reasons i have connected a second adsl connection with static i address aslo. Now my mail server uses the static ip of the one adsl connection. When the internet stops in one adsl connection i ought to connect the reserved adsl internet. Now my question is about the static ip address of the mail server. If i change the internet connection then also static ip address will change. Then how the mail server will use it? May i user 2 and more static ip addresses for one mail server? For example, now my mail server users x.x.x.x static address with example.com domain. May i also set y.y.y.y static ip address for it? So example.com should use 2 different static ip address? Is that possible?

If you have two connections which you want to use with Exchange, then you need to put a dual WAN router in front of Exchange and have the connections terminate there. Then the router will route the traffic for you. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources

hi, but each WAN router has its static ip address. And my mail server is registered to only one. If i change the router connection from one to other what about the static ip address? I mean my mail server is registered only one static ip address. in order to use the second static ip address DNS updates should pass and it takes 24 hours and maybe more.

That is why you have a dual WAN router. You can then have MX records pointing to both IP addresses. As they both arrive at the same device, email will flow correctly. The only other option is to have a second server of some description to act as an SMTP gateway. That of course would only be for inbound email. This isn't an Exchange issue, but a networking issue. The only thing you need to be aware of is that you cannot have two default gateways on a Windows server. Therefore if you want to run with two separate ISPs you need either a dual WAN router or two points of entry. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources

Yes. i have dual WAN router. each router is from different ISP. each has static ip addresses. for example, WAN N=1 ip address list: ip: x.x.x.x with subnet, gateway, and dns addresses. and WAN N=2 ip address is y.y.y.y with subnet, gateway, and dns addresses. Now my mail server user static ip address WAN N=1. So in the MX records only this static address is pointed. ok now. But if i want to change the WAN N=1 with WAN N=2, (wan n=1 is down for some time), i must point its static address to MX records too. And to do it, it takes 24 hours and maybe more. But during this time the mail server will not work in global network. My question is just to understand what to do in such situation: May i point two static ip address to MX records where the domain name situates? For example, pointing static addresses from WAN N=1 and WAN=2 to MX records. How is it possible? I want my mail address could be able to work with both of WAN connections immediately.

You are not limited to one MX record. If you already have the dual WAN router then just create a second host name that points to the second IP address and set it as an MX record. Email will then flow in correctly. Of course the problem with using two ISPs but one Exchange server for email delivery is that you can only have one of those set correctly for PTR and the SMTP banner. Therefore you may find that some sites reject email that goes out the second connection. The only way round that is to use a mail hop or mail relay service to route outbound email through, so that all email appears to come from the same place, and it doesn't matter which of your ISP connections it uses to get there. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources

What do you mean to create second host name? You mean, to install second mail server with second host name?

You can install a second server if you like, but this is all about DNS. Nothing to do with Exchange. I mean what I say - a second host name. If you aren't aware of how MX and DNS records work, then I suggest that you go and do some research. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources