Is there some problem with mx record of hotmail.com?

[ONG Liang Bu (CSC)]

Hi,

 

Just checking is this problem only happen to my site due to my ISP?

 

When sending to hotmail.com sometime we get the error of "Unknown TCP/IP hosts".

This problem not only lied with Exchange some of the Lotus Notes users also seeing it.

I do a nslookup and found that the mx record is a bit strange, some of the smtp servers

show on the mx records do not have IP address at the bottom.  Of all the smtp servers

only mx15, mx01 to mx06 has internet address shown.  Is this normal?

 

When I take one of the smtp servers that do not have an IP shown say mx10.hotmail.com

and do a "set q=any" check it can resolved to IP 64.4.49.135.  A manual connection to port

25 on this IP also successful.  But since this is only in "A" record will any mails to hotmail.com

go to this server?

 

Thanks for any guidance for this problem.

 

Ong LB

NIE

Singapore

 

> set q=mx
> hotmail.com
Server:  NS2.hotmail.com
Address:  216.200.206.139

 

hotmail.com     preference = 5, mail exchanger = mx15.hotmail.com
hotmail.com     preference = 5, mail exchanger = mx01.hotmail.com
hotmail.com     preference = 5, mail exchanger = mx02.hotmail.com
hotmail.com     preference = 5, mail exchanger = mx04.hotmail.com
hotmail.com     preference = 5, mail exchanger = mx05.hotmail.com
hotmail.com     preference = 5, mail exchanger = mx06.hotmail.com
hotmail.com     preference = 5, mail exchanger = mx07.hotmail.com
hotmail.com     preference = 5, mail exchanger = mx08.hotmail.com
hotmail.com     preference = 5, mail exchanger = mx09.hotmail.com
hotmail.com     preference = 5, mail exchanger = mx10.hotmail.com
hotmail.com     preference = 5, mail exchanger = mx11.hotmail.com
hotmail.com     preference = 5, mail exchanger = mx12.hotmail.com
hotmail.com     preference = 5, mail exchanger = mx13.hotmail.com
hotmail.com     preference = 5, mail exchanger = mx14.hotmail.com
hotmail.com     nameserver = ns1.hotmail.com
hotmail.com     nameserver = ns2.hotmail.com
hotmail.com     nameserver = ns3.hotmail.com
hotmail.com     nameserver = ns4.hotmail.com
mx15.hotmail.com        internet address = 65.54.236.7
mx15.hotmail.com        internet address = 65.54.232.71
mx01.hotmail.com        internet address = 64.4.55.71
mx02.hotmail.com        internet address = 64.4.55.135
mx04.hotmail.com        internet address = 64.4.56.135
mx05.hotmail.com        internet address = 64.4.56.199
mx06.hotmail.com        internet address = 64.4.55.7
> set q=soa
> hotmail.com
Server:  NS2.hotmail.com
Address:  216.200.206.139

 

hotmail.com
        origin = ns1.jsnet.com
        mail addr = dns.hotmail.com
        serial = 2002030401
        refresh = 28800 (8H)
        retry   = 3600 (1H)
        expire  = 604800 (1W)
        minimum ttl = 3600 (1H)
hotmail.com     nameserver = ns1.hotmail.com
hotmail.com     nameserver = ns2.hotmail.com
hotmail.com     nameserver = ns3.hotmail.com
hotmail.com     nameserver = ns4.hotmail.com
ns1.hotmail.com internet address = 216.200.206.140
ns2.hotmail.com internet address = 216.200.206.139
ns3.hotmail.com internet address = 209.185.130.68
ns4.hotmail.com internet address = 64.4.29.24

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