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Old 12-04-2003, 06:43 AM   #1
diegofalciola
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Registered: Dec 2003
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Angry Can't Connect to port 25


SOMEONE HELP MEEEEEEEEEEE!!

I have the sendmail daemon running at home, but noone from the outside can connect there.

I have read a lot about it, I have changed some options from sendmail.cf such as where to listen (0.0.0.0 instead of 127.0.0.1), tried to build my own cf, but nothing worked, Still cant connect to my server from the outside.

Does anybody know sth about this matter?!?!?

PLEASE HELP!
Thanks a lot!
 
Old 12-04-2003, 07:13 AM   #2
halovivek
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reply to ur message

could u please tell me what linux os ur working.
 
Old 12-04-2003, 07:22 AM   #3
diegofalciola
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Re: could u please tell me what linux os ur working.

Of course.

Is a Red Hat 9 Linux
Can you help me?
THANKS!
 
Old 12-04-2003, 08:17 AM   #4
brundles
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Are you running a firewall? Is it configured to allow port 25 through?
 
Old 12-04-2003, 08:35 AM   #5
diegofalciola
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Firewall

Yes, its behind a router firewall, cause server is on a maching behind NAT.
but does not even work on the server. seems to reject/drop connections to port 25, but routing to port 110 works fine, I dont know why.
I have tried, as you can read, several things, but nothing worked.

Hope sbd can help me =(

THANKS!
 
Old 12-04-2003, 09:53 AM   #6
zaphodiv
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Perhaps your ISP is blocking incoming connectios to port 25?
Run tcpdump on your internet interface, do you see an incoming SYN packet to port 25 when someone trys to connect?

what rule are you using to forward the traffic to the machine behind NAT?
 
Old 12-04-2003, 10:14 AM   #7
diegofalciola
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Firewall Roule

Is not an ISP problem, I called them and they are not blocking port 25.

I think that is an OS problem and i dont know why.
Using the tcpdump is a real mess, cause es a server. I will try to log connections.
My firewall roule to forward traffic is (refering to port 25)

iptables -A FORWARD -p tcp --dport 25 -o $INTERNAL_INTERFACE -d 192.168.1.2 -j ACCEPT
iptables -t nat -A PREROUTING -p tcp --dport 25 -i ppp0 -j DNAT --to 192.168.1.2


please, helppppppppp!!!!
 
Old 12-04-2003, 11:08 AM   #8
zaphodiv
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tcpdump -n dst port 25
 
Old 12-04-2003, 11:31 AM   #9
diegofalciola
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Angry NOT WORKINGGGG!

thanks to all, but this #$%@#$ still not working.
I have tried that "tcpdump...." with its parameters, but I receive no incoming connection to the port, seems to be blocked somewhere.

Any ideas!?

pleaseee IDEASSSSS! =$
 
Old 12-04-2003, 12:43 PM   #10
JordanH
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Registered: Oct 2003
Location: Toronto, Canada
Distribution: Ubuntu, FC3, RHEL 3-4 AS Retired: SuSE 9.1 Pro, RedHat 6-9, FC1-2
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Can you telnet to port 25?
 
Old 12-04-2003, 04:30 PM   #11
diegofalciola
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Telnet

I DO can telnet to port 25, but from my own computer, or from a LAN one, but not from the outside =(((

HELPPPPP!
 
Old 12-04-2003, 06:19 PM   #12
JordanH
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Sounds like a firewall issue. Would you care to post it so I can review what you have?

Your forwarding rules above look to be correct but there may be something before them that drops the packets.
 
Old 12-04-2003, 11:26 PM   #13
zaphodiv
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Hm, tcpdump might be listening on the wrong interface, you
may have to add -i ppp0

I'm not sure about your first forwarding rule. I'm not an ip tables guru but
I don't think you need the first rule, just the DNAT rule should do it.

>iptables -A FORWARD -p tcp --dport 25 -o $INTERNAL_INTERFACE -d 192.168.1.2 -j ACCEPT

>iptables -t nat -A PREROUTING -p tcp --dport 25 -i ppp0 -j DNAT --to 192.168.1.2

When testing remember that if the forwarding is in place then having somthing listening on port 25 on the server won't work, you have to remove the forwarding rule first.
 
Old 12-05-2003, 04:05 AM   #14
diegofalciola
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Firewall

Thanks all, but I already know that if firewall is running, redirecting port 25, it wont work on the server. To test it, the first thing i did was disable firewall and test it on the server. But didnt work. Yesterday I Changed my linux distrb. to Mandrake 9.2. Any more ideas?

I repeat, THANKS TO ALL!
 
Old 12-05-2003, 04:08 AM   #15
diegofalciola
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Registered: Dec 2003
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Didnt work either

I've tried to connect to my new Mandrake distr. but it didnt worked either. Here there is no firewall, no rules, no ipv4, just Mandrake just installed.
The problem seems to be port 25. I have read that there it was because of an issue that they block port 25 in sendmail.cf file. But evething I've tried, didnt worked.

Any more ideas?
THANKSSSSSS
 
  


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