remote mail clients can't send mail

[Geyybecca]

I have set-up sendmail in Redhat Linux 7.3, I am able to telnet to this server on port 25 & 110 so I know SMTP %pop3 are working. if I telnet on port 25 I am able to send e-mails to user@mydomainname.com I have set-up on that server.

my connect is broadband and 'always on' with a static live IP address, this server also provides DNS for 'mdomainname.com'

if I perform a nslookup from anywhere I can resolve mydomainname and the MX records are correct.

I have two problems

1) if I send e-mail from somewhere like hotmail I do not receive anything on the server

2) when at home and I connect to my linux box at work (the one running sendmail) I cannot send anything unless I lookup my current IP address and add it the the access.db if I do this then I can send out no problems, I am also able to receive anything I have send by telneting to the server

HELP !!! MCSE,MCSA,MCP+i,MCP

 

[fluid11]

Can your server resolve names on the internet correctly? Are there any blanket denies in your access table?

Chris

 

[Geyybecca]

yeah it can resolve no problems, by access list do you mean the access.db ? I have set localhost, localhost@localdomain 127.0.0.1 & the live IP to be allowed to relay. MCSE,MCSA,MCP+i,MCP

 

[fluid11]

What is the error message when you try to send from home, if the IP isn't in the access table? Its an unable to relay, correct? You should look into SMTP AUTH so that you can authenticate users who need to send, instead of having to manually add their IP addresses into the table.

http://www.sendmail.org/~ca/email/auth.html

**Ever considered using Postfix, rather than Sendmail? Its a much better MTA (IMO) and is much easier to configure -->

http://www.postfix.org.

ChrisP

 

[Geyybecca]

I have sorted the problem of remote users not being able to send. the problem I have now is receiving.

I'll explain the full set-up so everyone understands.

my Linux box is at work sat in the DMZ using a live IP address.

We have an internal network using the '10' network, on this network we have an internal DNS server and an Exchange server (NOTE: this exchange server has a mapped live ip on the same network as the linux box) this linux box also acts as our external DNS server.

If I configure our internal DNS server to use our external DNS server for names it cannot resolve I can send email from my internal work account to my sendmail acocunt.

If I then change our server to use another DNS server I get nothing and no NDR (not as yet anyway)

First thing I checked was can mydomainname.com be resolved, yes it can I have trebble checked this the MX record comes up fine.

I am thinking somewhere in the sendmail config it is accepting mail only if it is pointed to it by the authoriive DNS server ?

as mentioned before I can telnet on both port 25 & 100 MCSE,MCSA,MCP+i,MCP

 

[fluid11]

Since your Sendmail box is inside a DMZ, there is probably a firewall or router in front of it on the WAN side. If I did an nslookup on your server right now, would it return the IP address of your Sendmail box or a firewall/router? If there is a firewall/router in front of the box, are ports 25 and 110 open and forwarding to the server?

Chris

 

[Geyybecca]

its certainly not a firewall issue for the perpose of setting all ports in and out are allowed and if you peform an NSLOOKUP its live IP is returned. Also I can ping and telnet on port 25 to mail.mydomain.com from my dialup account at home. this has made me rule out DNS as an issue MCSE,MCSA,MCP+i,MCP

 

[fluffybunny]

Are you using the default sendmail.cf config file or did you generate a new one with the sendmail.mc ? Did you add in anything to the sendmail.mc file ?

Regards.

 

[Geyybecca]

well would you believe I can receive e-mails from anywhere except hotmail & microsoft (I have a freind who works there)


there is no denies for MS or hotmail in the access list so no idea why they can't send.... MCSE,MCSA,MCP+i,MCP

 

[fluffybunny]

Try going to

http://ordb.org/

and do a lookup to see if your site is listed under the blacklisted sites. If you are, you may have some problems in sending and receiving mails from certain sites that incorporate blacklist feature listings.

Regards.