How to find a machine acts as mail server?

[Lakshmipathi]

Hi,
I want to know whether a machine (say ip:10.232.13.13) is mail server or not?
How to know that...any commands like ps or pgrep or ping or telnet will help me?
Please help me.

[redthree]

Hi there,

if you telnet to the ip address, and suppy port 25 (SMTP protocol), you should get a welcome message from the server. you can actually interactivey check your mail in this mode. Alternatively, you could just point a mail client like Thunderbird at the server using the ip/host name and the default ports and try to send a mail. if you get a meaningful error message (rather than connection refused) you will know a mail server exists.

[Lakshmipathi]

Hi,
thanks for reply.Ok can telnet to the system and use interactively with the server.
So i guess it's mail server only.
But can it be relaying mail server?-ie. just relay mails to another original mail server?
Is that possible??

[redthree]

Hi there,


It is possible that it is a mail relay only, although often servers are multi-purpose depending on the environment.

There are a few other things you can try to test and see what else is going on.

You can try using telnet to the POP (post office protocol) service on port 110 or IMAP on port 143; again you should get an interactive session rather than a connection refused. You can also try and SSH, or telnet to port 22 to see if this has any service running. This should give you some idea whether the server has other uses or not.

Often, if the server is more than an internal relay, the IP Address will map to a hostname somewhere. Can you ping the IP Address you are testing? If you ping the IP Address, it shoud resolve to a hostname and return that. If you can resolve the hostname directly (in your browser or by pinging the hostname rather than the IP) then that server will likely be used as an inbound and outbound mail relay.

[Lakshmipathi]

Hi there,


It is possible that it is a mail relay only, although often servers are multi-purpose depending on the environment.

There are a few other things you can try to test and see what else is going on.

You can try using telnet to the POP (post office protocol) service on port 110 or IMAP on port 143; again you should get an interactive session rather than a connection refused. You can also try and SSH, or telnet to port 22 to see if this has any service running. This should give you some idea whether the server has other uses or not.

Often, if the server is more than an internal relay, the IP Address will map to a hostname somewhere. Can you ping the IP Address you are testing? If you ping the IP Address, it shoud resolve to a hostname and return that. If you can resolve the hostname directly (in your browser or by pinging the hostname rather than the IP) then that server will likely be used as an inbound and outbound mail relay.

Thanks and got a problem yesterday i can telnet into port 25 of the machine ,
But it says ,

:connection refused.

whats it mean?
and when i
telnet to 110 or 143
its says,

Trying 10.232.13.99.....

But i can telnel to 22 port
and i type the ip-address on browser i'm getting apache running screen.

[Lakshmipathi]

Often, if the server is more than an internal relay, the IP Address will map to a hostname somewhere. Can you ping the IP Address you are testing? If you ping the IP Address, it shoud resolve to a hostname and return that. If you can resolve the hostname directly (in your browser or by pinging the hostname rather than the IP) then that server will likely be used as an inbound and outbound mail relay.

i can ping to that address.But it doesn't display any hostname.