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Author Topic: Howto open ports 25 and 110?  (Read 3321 times)

Offline Timur

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Howto open ports 25 and 110?
« on: February 09, 2004, 05:37:49 AM »
I have a proxyserver on squid with one network interface (eth0) and ADSL connection. Internal computers use a certain accounting software which needs ports 25, 110 to be opened so that they could exchange some data with other PCs outside the lan. I know that squid cannot do this. I also was told that I should play around with iptables to open these ports. Can you tell me how to do this? :?:
Particularly, could you give me a list of commands that will help open 25 and 110.

Thank you.

Offline Ricky

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Howto open ports 25 and 110?
« Reply #1 on: February 09, 2004, 05:53:41 AM »
You are saying that you want to open ports.. i think those are used for smtp or pop..  Well if you are already having a script for firewall then add the following lines to your script at the end.. If not then add the following lines to your /etc/rc.d/rc.local in the end.. But be sure that those lines will delete any existing rules.. you can ommit the line i have commented with '#' .
Code: [Select]
IPTABLES = /sbin/iptables

$IPTABLES -A INPUT -p tcp --dport 25 -j ACCEPT
$IPTABLES -A INPUT -p tcp --dport 110 -j ACCEPT

For squid.. make a acl like..
Code: [Select]
acl ext_ports port 25 110
http_access allow ext_ports

Offline Timur

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Howto open ports 25 and 110?
« Reply #2 on: February 09, 2004, 06:32:25 AM »
I did everything as you wrote plus I opened port 53 (one of my friends told me to do so) and I even restarted the whole linux box to make new rules apply for sure. However, I still can't telnet pop and smtp servers from inside the lan. I wrote other iptables commands before. Do I have to delete them first if they are conflicting somehow with rules that you gave me? Or there is anything else? Please, help me!

Offline Ricky

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Howto open ports 25 and 110?
« Reply #3 on: February 09, 2004, 10:45:42 AM »
Do you have any other script running on your system regarding iptables.. such as firewall... then show that to me..

Offline Timur

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Howto open ports 25 and 110?
« Reply #4 on: February 09, 2004, 11:00:44 AM »
Well not to my knowledge. I did not write any scripts for firewall regarding iptables. This server was dedicated only for running proxy server, that's why what I did was that I configured squid only. You know, I talked to our ISP and they offered my to write the following rules to my rc.local file:

iptables -t nat -F
iptables -t nat -A POSTROUTING -s 192.168.x.x/24 -p tcp --dport 110 -j
SNAT --to-source 81.95.x.x
iptables -t nat -A POSTROUTING -s 192.168.x.x/24 -p tcp --dport  25 -j
SNAT --to-source 81.95.x.x
sysctl -w net.ipv4.ip_forward=1

where 192.168.x.x -- IP address of my network
and 81.95.x.x -- IP address of our IP address given by our ISP.

And I did put 'em in. However, it did not work. I'm checking with outlook and still cannot connect. Neither can I telnet for example pop.mail.ru 110 server. Maybe I'm doing something wrong. There has to be some decision. Thank you for your patience.

P.S. do I need to type $ sign in front of the word "iptables", and what does $ sign mean?

Offline Ricky

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Howto open ports 25 and 110?
« Reply #5 on: February 09, 2004, 11:10:48 AM »
First of all.. Did u you undergo this .. http://www.linuxsolved.com/forums/viewtopic.php?t=116

That is what you are looking for... it is not the problem of opening port.. also see the NAT script there .. link is given.. and in NAT script add eth0 or which NIC is connected to ISP in the place of ppp0