Re: Configuration Problem

At 02:39 25/08/2013  Sunday, Roman Gelfand wrote:
>Thanks a lot for your advise.  I didn't even realize that yahoo could
>be relaying from one smtp server to another within their network.

no large isp uses either the same ips for sending as receiving or uses any non tiered clustered load-balanced approach

even small isps like the ones i work for may have only a few physical servers but we will have a different ip for sending and receiving on each (as it makes securing and load balancing easier

(one or more inbound ips load balanced to the least stressed server) 
one dedicated ip per server for outbound so we can know which servers logs to check if we get a complaint of bad mail from xyz ip


>Anyway following your lead, I did a dig on smtp.bizmail.yahoo.com and found this
>
>smtp.bizmail.yahoo.com. 295     IN      CNAME
>smtp.bizmail.mail.fy4.b.yahoo.com.
>smtp.bizmail.mail.fy4.b.yahoo.com. 295 IN CNAME
>any-smtp.bizmail.mail.fy4.b.yahoo.com.
>any-smtp.bizmail.mail.fy4.b.yahoo.com. 295 IN A 98.139.221.242
>any-smtp.bizmail.mail.fy4.b.yahoo.com. 295 IN A 208.71.40.208
>any-smtp.bizmail.mail.fy4.b.yahoo.com. 295 IN A 98.138.105.25

ok its interesting as it shows somehow how the load balance their receiving side
as id guess the fy4.b alters each lookup (or over time) to point at the next least loaded cluster


>I, then, looked up whois and found these fall into 2 huge networks
>98.136.0.0/14
>208.71.40.0/21
>
>Is this range should be all they have or do you think there is more
>and I need fish around more?

there is likely more
at least 
<http://whois.arin.net/rest/poc/NA258-ARIN/orgs>http://whois.arin.net/rest/poc/NA258-ARIN/orgs 

http://whois.arin.net/rest/org/YAOO/nets 
<http://whois.arin.net/rest/org/YAHO/nets>http://whois.arin.net/rest/org/YAHO/nets 
http://whois.arin.net/rest/org/YAHOO-1/nets 
<http://whois.arin.net/rest/org/YAHOOI-2/nets>http://whois.arin.net/rest/org/YAHOOI-2/nets 

and thats just the US based ones their is a good chance they have blocks in other cheap hosting countries too

as i said 

A forget smtp.bizmail.yahoo.com

B send yourself mail via yahoo (to gmail or this list)
or even direct to me and I'll send you back the ips

C look at the ips/names that the mail comes from (only), these are the blocks yahoo uses to send your mail
(they maybe within the same ranges, they may not, either way their sending ips are all your interested in, not their receiving ones like smtp.bizmail.yahoo.com)

you might find they only send from a very limited range based on your username
(as i cant see them placing all customers in the one basket they would likely use different ranges for free service customers to paying, as they don't want one services reputation damage (spammers-on the free webmail) causing harm to all (or maybe they do, who knows)

>Thanks again for your help

it would be much easier if you just used the domain in question on-list we would already have 2 sending ips to look at

yahoo might be the one and only excuse for using the ptr: record, but i still think