how emails are sent/routed ?

chamjiee

hi
i am working in an orginaztion as level 1 support technician. reading nms and email ndrs are my achiles heels.
can someone tell me how email are routed ?

we are using exchange 2010 servers. and we are also using microsoft spam filter solution.
i would be glad if someone could clarify how emails are sent from our exchange to outside world ?
does it reaches destination server directly or through some intermediate email systems (like microsoft antispam solution) ? like in routing protocles ?

i want to be able to read and interpret NDRs.. and make a sense of it.

dhenderson

Email internally is routed through AD site links. The Hub transport controls the routing of mail. Anything external goes through the Hub Transport and out to the internet. This can go through the Edge Transport (anti spam) but usually organisations send their mail to an antispam email filtering system on the way out.

Does this help?

chamjiee

dhenderson wrote: »

Email internally is routed through AD site links. The Hub transport controls the routing of mail. Anything external goes through the Hub Transport and out to the internet. This can go through the Edge Transport (anti spam) but usually organisations send their mail to an antispam email filtering system on the way out.

Does this help?

thanks i knew it .. i wanted to know a bit beyound.

i have a bit of networking background ccna. as in routing world we have routing protocols to gather info about the differnet ip networks . and to reach a destination we go through several hops as is shown by trace route.

i wanted to know how email is sent ? does it goes through some intermediaries ? and which intermediaries.. say we have edge server and configured microsoft spam filter as anti spam solution?

because reading NDRs i see a lot of server addresses how to decipher and make sense of those servers ?

dhenderson

I mean really you should only be concerned if mail is leaving and being recieved your organisation. You will know the name of your gateway server etc. Its best to look at the message tracking logs to see it leaving, comiing in.

I think it works like routing, say you send an email to bob@contoso.com, the email will go off into the cloud and will the servers will push the mail through to the destination. So Server A will send it onwards and then go to the next hop which willl be Server B and so on.


Can someone expand on this?

tomtom1

chamjiee wrote: »

i wanted to know how email is sent ? does it goes through some intermediaries ? and which intermediaries.. say we have edge server and configured microsoft spam filter as anti spam solution?

Answer is, it kinda depends. In your Exchange server (Hub Transport for example) you can configure to send the mail to persons out of your organization based on the MX record(s) published in DNS, or you can route them through a smarthost, which can be something like the Microsoft spam filter (if they do outbound spam filtering).

On the receiving end of that mail, the same process actually takes place. Some (most) organizations have something like an inbound spamfilter which cleans the mail first before delivering it to the next server in the path to the destination mailbox. That spamfilter will then be mentioned as MX record in the DNS zone of the receiving domain.

If you're having trouble with deciphering NDR's, you could anonymize them and post them here, and mention what is not clear to you. We could help you understand then.