Remove SmartHost from SBS2008 Server

Can to give me a little more info on how to do each?

First try to open Internet explorer and check if sites are opening fine.

Do NSLOOKUP in command prompt and type the domain name on which you are sending mail e.g. you are sending mail to amit@abc.com so in after opening NSLOOKUP type abc.com

Once it is resovled
then follow the below one:

Open command prompt --> Type NSLOOKUP and hit Enter

type abc.com

If it gives you result as IP address and domain name then follow:

set q=mx

now type again abc.com

It will show MX records published for abc.com

copy all MX records and IPs now close command prompt

Then try to telnet MX records

open a new Command prompt

Telnet <mx record> 25 and hit enter
then type ehlo, if it is responding then all OK, but if it is not responding then check with Network level.

I think we are crossing directions here which might be OK because mail isn't flowing wither way. I started on my computer here in the office and did the above steps to their SBS Server. The NSLookup seemed to go OK except for the very first reply where is said the Address is 64.29.145.9 That is their web page. Results are attached. The MX Record and Internet address looked fine. That is their public IP. I did a Telnet mail.vancontracring.com and 25 and it timed out. So best guess is port 25 isn't forwarded to the SBS 2008 Server? (inbound).

It should telnet to this MX record if it is not then check with other domains.

Thanks Amit. I for some reason have never been able to use that Telnet trick. I don't know what I am doing wrong. It is one of the oldest tests in the book but I for some reason can't get it to work and have never been able to.

   Anyway... I looked through their firewall and found where they limited inbound port 25 to certain IP addresses and opened it up to where they are now receiving mail (even though the telnet test doesn't work). SO I am down to them not being able to send.

   I got on one of their workstations and sent an email to me at my office. It is stuck in the queue. This is the part when I changed them from a smart host for sending to just using MX lookups. I know my email address is good. I have been getting your emails all night. Theirs don't send since I removed their smart host. The type is DNSConnectorDelivery. Any idea what to try on their outbound?

also check the permission for the send connector..

Well..... if it helps I finally wound up putting the smart host back in. I'd really like to get it to work with MX lookup. Any idea?

Your server must be able to access port 53 and 25 out to the internet, otherwise your DNS lookup will not work along with mx lookup and emails will not be sent out via port 25.

firewall rule should be:

server ip -->> ports 25,465,587,53   --> wan (any)

once you get it done you can start sending emails..

G

Thanks Giladn. The firewall was a mess but to test that issue last night I made up a rule to allow all outbound and moved it up to the first position. It didn't seem to help but maybe I didn't wait long enough.

   If 53 was blocked would it affect where they go on the internet? They don't have any internet issues.....

Everything went fine:

Yahoo.com resolved

Telnet worked as you said it should

MX Toolbox did not report it on a blacklist

I did notice in goggling the error 451.4.4.0 that it is a pretty common problem on E2007......

see if this helps:
http://exchangeserverpro.com/messages-queuing-error-451-4-4-0-dns-query-failed/

next, try this from Exchange management shell:

New-SendConnector -Name "send connector" -Usage Custom  -AddressSpace "*;1"," -DnsRoutingEnabled $true   -MaxMessageSize 20MB