port question

[Tony Alfrey]

David A. Bandel wrote:
> On Sat, Aug 22, 2009 at 22:26, Tony Alfrey<tonyalfrey at earthlink.net> wrote:
>> Consider Alice, Bob and Tony.
>>
>> Bob and Alice are computer illiterate, Tony perhaps less so.
>>
>> Bob sends email to Alice's POP server.  For some reason, Alice's POP server
>> does not receive this mail, or more accurately, does not process it.
>> Bob sends the same email to Tony's POP server, no problem.
> 
> First, a pop server is a post office protocol server.  It uses port
> 110 or port 995.  SMTP uses port 25 or another port.  Unofficially,
> 465 is the SSL port.
> 
> You send mail to an e-mail server, not a pop server.

Yes, thanks, I've been reading some and I've now figured out that 
difference.

> 
> Unless of course you're referring to point-of-presence.  But don't
> call it a server, it's just their POP.
> 
>> Tony says to Bob:  "What port are you using for your SMTP server?"
>> Bob says "Say what?"
>>
>> Tony says to Alice: "Does your POP server perhaps block port 25?"
>> Alice says "Say what?"
>>
>> How can Tony examine the incoming e-mail to know the port?  Tony does not
>> host a server, so Tony cannot receive the raw packet stream, Tony can only
>> read the e-mail after it has been received by Tony's POP server (more
>> accurately, the POP server for Tony's domain hosting service).
> 
> Why would Tony need to examine incoming mail?  If he wants to know if
> port 25 between himself and Alice is blocked, all he has to do is:
> 
> telnet "Alice's email server" 25
> he can connect or not.

I will try something like that.  Turns out the problem is between Bob 
and Alice.  No problems between Tony and/or BoB and/or Alice.  Tony is 
simply the diagnostician.

> 
> To find Alice's email server:
> dig MX "Alice's e-mail domain"
> 
> BTW: ports don't show up in e-mail headers, only IPs.

I've learned that, too, since posting.

> More likely,
> Alice's spam filters are plonking Tony.

plonking Bob.  Yes, that is what I've concluded.
I'm thinking it's not a block of Port 25, 'cause Tony's incoming mail 
server (earthlink) already blocks Port 25 and Tony gets mail from Alice 
and Bob.

> 
>> Thanks in advance.
>>
>>

Thanks Dave.


-- 
Tony Alfrey
tonyalfrey at earthlink.net
"I'd Rather Be Sailing"