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Legacy Forums => General Discussion (Legacy) => Topic started by: Ian on September 05, 2003, 06:22:17 PM

Title: Port 25 open?
Post by: Ian on September 05, 2003, 06:22:17 PM

I have a sme 5.6 U4 and I tested my system with a couple of on-line port scanners. I found that http://scan.sygate.com/ says my port 25 is open yet http://security.symantec.com/sscv6/home.asp says its closed. I thought as standard it was closed to the WAN side of the box. I set a user account up for my brother in the UK and he set the SMTP address as my SME box address and was able to send mail when it was addres to my SME domain name but would not accept anything other than my domain in the email address. Can some one tell me if this is correct or have I got some problems here?

Thanks in advanced.
Ian

Title: Re: Port 25 open?
Post by: Dave Liquorice on September 06, 2003, 03:56:31 AM

You don't say what mode you have your SME box in, I shall have to assume server/gateway not private server/gateway or server.

What you see of your brother being able to send mail only to your domain and no other is correct.

If he couldn't send to your domain neither could anyone else...

If he could send to anywhere else so could anyone else and you would be rapidly found as an open relay. The spammers would then pour their mail through you.

Why the two port scanners report different things, well you'll have to see what each is testing for. Is one just looking for ports with services behind them and the other specifically for an open relay?

Cheers
Dave.

Title: Re: Port 25 open?
Post by: Ian on September 06, 2003, 04:06:49 AM

Thanks Dave

I will look deeper into what they were searhing for but on the surface I think they are there to look for security holes. You are right about the server/gateway sorry I should have mentioned that. I was checking because someone on my ISP may have an open relay as some sites have blacklisted my ISP and mail was returned. At least I feel better to know it is working as it should.

Thanks again

Ian

Title: Re: Port 25 open?
Post by: Doug M. on September 06, 2003, 10:47:59 AM

If you want to check to see if somehow your system is being used for a relay there are several sites that can run a quick test to see if your system will allow relaying. One is or just run a google search for one.

http://email-test.com/cgi-bin/webtestmail?cmd=show_openrelay

Title: Re: Port 25 open?
Post by: Ian on September 06, 2003, 06:04:15 PM

Thanks Doug, all passed with flying colours. : -)