Software :: Sendmail - Telnet Not Connecting On Port 25?
Jan 11, 2011
I have been trying all day today to setup a sendmail SMTP server on our Red Hat 5.5 dev box. We have 2 network cards, 1 to the local network with a 192.168 prefix and an external card which goes out to the web through a BT leased line through a Cisco router.
First I followed one of the many helpful tutorials online to setup sendmail, installed all the required packages and made a couple of small config changes to allow the service to listen on all IP addresses rather than just the localhost 127.0.0.1.
The main change is in the /etc/mail/sendmail.mc file where I have changed the following line;
I have tried removing Addr completely, setting to either the local or external IP and then rebuilding the sendmail file using 'make -C /etc/mail' and then restarting using 'service sendmail restart'
The SMTP port has been added into the firewall and it is showing to be listening on IP 0.0.0.0:25 which I believe means it is listening on all IP's assigned to the machine, sendmail is also in listen mode and running correctly.
Finally I have changed the /etc/mail/access file to include the local IP range 192.168 and external IP range and rebuilt this into the /etc/mail/access.db file and then restarted sendmail.
Googling the error all the sites I have found talk about making sure the 'DAEMON_OPTIONS(`Port=smtp,Addr=x.x.x.x, Name=MTA')dnl' line is uncommented and not much else in terms of what else might be incorrect.
I am starting to run out of ideas on things to change or check, telnet works correctly on other ports on the same server, ie httpd for apache on port 80. I have also rebooted the server to make sure that it wasn't something odd happening.
I seem to having some strange issues with my new sendmail server and was hoping that somebody can offer some assistance with this issue. I recently tried to setup an enviromental monitor that sends alerts via email using a dedicated email account I created on my sendmail server. For whatever reason, it does not seem to be able to send emails, and I have verified the account credentials multiple times.
So I attempted to run a telnet SMTP test to determine what the problem was. I was able to connect and send the emails using this test perfectly fine from my local subnet, however I ran into problems attempting this test from the outside world. When I connect the SMTP PORT 25 from the outside world, I get what seems to be a malformed SMTP greeting.
In my home we have got an internet connection which is connected to desktop machine having two network cards. One card is connected to external internet and second is used for internal LAN.
We have installed a proxy on desktop machine so that we can connect to internet through proxy. So we are not able to telnet to smtp.gmail.com 587 from laptops of internal LAN laptop installed with ubuntu and fedora.
At the same time we are able to ping smtp.gmail.com from the desktop machine which is exposed to internet.
I want to automate email through shell script using smtp.gmail.com.
I am trying to open the telnet port on my system with port 4100 and for the same i have inserted the entries in iptables file using below command./sbin/iptables -A INPUT -s 132.186.208.83/24 -p tcp �-dport 4100 -j ACCEPT.
I'm trying to test smtp connectivity to my postfix configuration and I can telnet to port 25 from the computer itself but cannot from the outside. I get a connection refused error message. What am I doing wrong? I believe my dns is setup correctly as it seems the telnet can hit the box so I'm fairly sure its not that.
Sent an email by using telnet on port 25 from the terminal. Telnet states my message was sent but I never got it. Is it on the hard disk somewhere. Is there a log file? Where did my email go? Did it go into the ehter? I opened port 25 on my firewall through gnome by selecting 25/smpt checkbox as a trusted service.
I have a customer who is complaining that they can connect to prt y on IP x with telnet. They are seeing the following:
telnet x.x.x.x y Trying x.x.x.x... Connected to x.x.x.x. Escape character is '^]'.
after some time the connection of course times out. Connection closed by foreign host. There is no telnet service running on this port so they cannot do anything, but they are complaining tht the fact that telnet "connects" is a security risk. I am having difficulty explaining why they are able to connect with telnet. I know it has to do with the socket layer API in Linux but I am having difficulty explaining this sufficiently. I also can't just say "this is the way linux works" to them. I am looking through "UNIX Network Programming" by W.
I'm trying to capture incoming/outgoing phone call data. Both telnet and nc have allowed me to easily direct this data to a file for later processing, HOWEVER I can't seem to get either to work as a background process. I want to put the connection into a shell script and run from cron.
Trying 192.168.100.9... telnet: Unable to connect to remote host: Connection refused
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This last one is strange as I the IP looks odd.
What I am doing wrong, and how do I fix it. After much surfing many mosts say that telnet is not used anymore but I want to use it to test my smtp server.
Sendmail on the RHEL server is set up to forward email to company internal mail server (via SMART_HOST). This has worked fine for years.
From the server, doing a sendmail dave@company.com, the message is sent immediately. No problems - and no change here.
From the server, doing a sendmail roberto@compania.com (compania is the part of the company in Mexico) causes a 2m40s delay before sendmail does anything.
No packets are sent until after 2m40s wait. Message is always sent after the delay. It is not clear what the server is waiting for.
For *each* user in the @compania domain specified in sendmail command, an additional 2:40 is imposed before email is sent. Email is always sent after the n*2:40 sec delay.
Sending email to some_name@AnUnusedDomainNameThatDoesntExist.com is processed immediately - with a bounce email received in a couple of seconds.
Q: How do I determine where this 2m 40s delay is introduced?
possible to run Qmail and Sendmail on one server, both on another port? I need qmail for Plesk and sendmail for OpenEMM Now qmail is working for plesk, but if I install qmail ( I tried install it also from source) and try to run sendmail, I still get this error: Starting sendmails: listener sendmail: illegal option -- q chich probably means, that there isnt full sendmail version.
My problem is that when i try to open port 25 with telenet it takes lot of time like more than 1 minute to open session and another 30 - 40 seconds to respond to "ehlo" command.
Also when i try to open telnet session on port 25 in another server it hardly takes 1-2 seconds open session.
I have configured a sendmail MTA for incoming mails in a network and by using IPtables i have redirected the traffic internally to other port where one more SMTP by a application is running.Iptables rule:
I have changed over to AT&T U-verse. I need help getting my sendmail able to send out.
From AT&T website Incoming mail port number: 995 (make sure secure connection (SSL) is checked) Outgoing mail port number: 465 (make sure secure connection (SSL) is checked)
how to setup sendmail to use SSL , userid,password and port 465 ?
Ok, a bit of a backround. I am a recent Ubuntu user and made the switch to Fedora being utilized as a server. I am trying to move to a new MUD(text based D&D type game) codebaseI have gotten my code compiled and executed the startup script. The process shows in the ps ux list. As the game it set up it uses port 7500. As the script running I get a "Connection Refused" error when trying to telnet to port 7500. Upon using nmap, I show only my SSH port open (the only daemon I have installed currently) yet no port 7500 open.
I believe this to be an issue somewhere in Fedora as I've had no issue on Ubuntu with past MUD codebases.I have disabled the firewall within Fedora and still no luck. Please bare with me as I'm new to fedora's intricacies.Short Story for those that hate reading long winded posts: A port that should be open by acript known to work on other distro's doesn't seem to open the called port using Fedora
i make this script to become a service ( i test it from bash, and my script work good), my problem is when i telnet to my local host (127.0.0.1) via a personal port like 5555 telnet give this error: ")syntax error: invalid arithmetic operator (error token is ", i know this error is for echo $(($A+$B)) and i know that telnet can not calculate $A+$B and the error is for this
I went and generated a self signed SSL .pem file ($1000 for a signed wildcard ssl certificate is out of my price range at the moment). I can connect to my server on port 26 when using STARTTLS but not SSL/TLS mode. I would like to be able to connect to port 465 on SSL mode, but I have no idea how.
I'm looking forward to know how to connect to a remote server through SSH but from a specific port, so I con drop connections from random ports that's not the one I choose. Is this possible?
I have tried by setting up an iptables entry to forward output through both, PREROUTING and OUTPUT (one at each time, flushing when I can see that it's not working), in NAT table, so I can connect doing ssh localhost
I want to do this because I think that doing this will enhace the security, dropping connections of clients that are trying to connect from not allowed ports. I have already set up fail2ban and created SSH keys, not allowing to login with password, only key allowed. Will only allowing connections from a specific port will enhance the security or not really?
I am a student in Information Technology . I have a question from the book of Mark g.Sobell . I could not find the answer for that .Why might you have a problem connecting to an FTP server in PORT mode?
Using a fresh Ubuntu server install, i setup UFW :
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When connecting from external box to this server on port 25, the connection is properly blocked by UFW but i can't find any UFW log (/var/log/kern.log, /var/log/messages, /var/log/ufw.log ...). I'm using default rsyslog.
- I've recently been donated a second emac by a friend that needs a new hdd. I want to add as much speed as possible, but don't know much about hdd transfer speeds
1)sub 100 SSD vs 7200 16mb 3.5'' platter drive ? I can't seem to find much information here. As far as I can tell, the standard hard drive would be faster unless I'm prepared to spend a couple of hundred on a top of the range SSD - is this correct?
2) will a sata/ide converter slow the transfer rates? is it worth spending the extra 50% to get an ide drive with the same specs as a SATA drive, or just use the converter?
3) Thoughts on connecting the drive via firewire - how much slower would this be than connecting the drive via the ide port on the motherboard? I am only concidering this as I don't use the firewire ports for anything else, and getting to the hard drive is a total pain, not to mention the inherrant risk of electric shock on these machines.
whose only way of connecting is trought a serial cable like the one used for a monitor but on the reversed, (sorry i dont know the correct term), ive tried using hptalx and kermit to no avail if someone could poinme in the rigth direction wolud be much apraciated, (i'll be having, some exams soon, so im in a bit of trouble), distribution slackware 12.2 , kernel 2.6.27.31 (i think).
1. Need to connect 2 CCTV DVRs and view from remote. 2. Can get a static IP address. But I dont know if this is a secure way since any once can view if the know the ip address. 3. Question is : is it possible to connect the DVR( s) to a linux server which will get user name and password before letting us view the DVR. Currently there is one set as follows: 1. From location X a device is connected to location Y using leased line and static IP (12 kms distance). In location Y a router is placed and port forwarding is configured. From Location Z using internet and remote desktop concept the device at location X is viewed and data captured. Is it possible to use a similar concept but with some sort of security authentication procedure in place.
