Thanks. I got enough reasons to convince the user that this is not a good idea :-) ________________________________ From: exchangelist-bounce@xxxxxxxxxxxxx [mailto:exchangelist-bounce@xxxxxxxxxxxxx] On Behalf Of Jason Sherry PE Sent: Tuesday, October 03, 2006 1:05 PM To: exchangelist@xxxxxxxxxxxxx Subject: [ExchangeList] Re: use dynamic ip address for mail server Rick is right about the reverse lookup. Aol, yahoo, hotmail, etc are now blocking e-mail from hosts that their PTR (reverse DNS record) doesn't match the sending DNS name. See: http://support.microsoft.com/kb/924235/en-us For example, if you have the IP of 1.1.1.1 and your server sends out an e-mail as mail.faranheit.com the receiving server, if enabled, will do a reverse lookup on 1.1.1.1 and get something like dynamic-1-1-1-1.isp.net. Since this doesn't match mail.faranheit.com the receiving server might reject the e-mail or flag it as spam. I would HIGHLY suggest going with a static IP, it should only cost $10-$20/month extra, and your ISP should let you create a PTR record for your IP address. The other alternative is to use your ISPs for sending SMTP mail or another SMTP server, this will require some changes to the default config of Exchange. Jason Sherry - Pro Exchange http://www.theproexchange.com <http://www.theproexchange.com/> From: exchangelist-bounce@xxxxxxxxxxxxx [mailto:exchangelist-bounce@xxxxxxxxxxxxx] On Behalf Of Rick Boza Sent: Tuesday, October 03, 2006 12:42 PM To: exchangelist@xxxxxxxxxxxxx Subject: [ExchangeList] Re: use dynamic ip address for mail server I think it's risky, and certainly isn't a best practice, but should work. See http://www.amset.info/exchange/dynamicip.asp and http://www.msexchange.org/tutorials/MF002.html for short guides. I would imagine there could be delivery delays from time to time if you get between updates. I suppose its also possible you could lose some mail if somehow you wound up where someone else with an SMTP server gets your old IP address, and rejects the message as undeliverable...but that seems really unlikely. I can also see you getting rejected by some orgs doing a reverse lookup, they may not like you redirecting from mail.domain.com to domain.dyndns.org Having said that, personally I think a much better solution would be to put the server somewhere that you can support a static address, and point the clients to it via RPC/HTTPS. Plus, static addressing isn't that expensive anymore - what's the price difference? With Sprint I think the difference runs around $20 / month. When talking to clients that insist they can't afford to do something according to a best practice, maybe they need a different solution? Just my random thoughts, anyhow. Rick Rick Boza Protechnica 407-656-9744 rickb@xxxxxxxxxxxxxxx Manage Your Mobile Workforce! www.findmeusa.com/pro From: exchangelist-bounce@xxxxxxxxxxxxx [mailto:exchangelist-bounce@xxxxxxxxxxxxx] On Behalf Of Ara Avvali Sent: Tuesday, October 03, 2006 2:22 PM To: exchangelist@xxxxxxxxxxxxx Subject: [ExchangeList] use dynamic ip address for mail server Greetings, We want to host a mail server at a DSL line which is dynamic. Getting static will cost a lot of money at the location so we got a linksys router that support dyndns.org and created a record for domain.dyndns.org. Put the router in front of mail server and forwarded tcp 25 to mail server. Then we create a CNAME in DNS server that mail.domain.com points to domain.dyndns.org. Then there is an MX record with 10 priority mail.domain.com. Would this work? It is almost 24 hours and dnsreport still says there is no proper mx record configured. I appreciate any help on this one