bluegroper
Technical User
Problem sending email
I have an "off-line" postfix mailserver. It does a great job for a small and busy office.
It handles LAN email, as well as relaying outgoing email to the isp's mailserver.
Relayhost = mailserver.isp.com.
Incoming email is pulled from the isp using fetchmail, and handed on to postfix for local delivery.
It all worked perfectly for ages, until I replaced the NAT router with a "proper" firewall-router, IPCop. IpCop standard version 1.3 with all fixes and port 113 closed off too. Also, it won't respond to pings. grc.com reports it as "Fully Stealthed". No port forwarding setups, either. Hoping I wouldn't need that.
Now the incoming email (fetchmail -> postfix thru IpCop Box) continues to work just fine. But outgoing email is stuck in the postfix outbound mail queue. The error message from the postfix maillog says "Name service error for mailserver.isp.com: Host not found, try again". This is confusing because I can ping and traceroute from the postfix mailserver to the mailserver.isp.com. The dns lookup seems to be working just fine.
Also, from LAN workstations I can send email directly to mailserver.isp.com using port 25 with Eudoras, Outlooks, etc. This is going quite happily thru the IpCop box. My preference is to route this outgoing email thru the postfix mailserver for outbound relaying, simply because its more efficient. Speeds up the LAN workstations and the postfix server can just sit there delivering email like its supposed to.
So if Outlooks and Eudoras can send email to mailserver.isp.com using port 25, why can't postfix ?
My dilemma is whether this is an IpCop or a postfix issue.
All suggestions gratefully received.
I have an "off-line" postfix mailserver. It does a great job for a small and busy office.
It handles LAN email, as well as relaying outgoing email to the isp's mailserver.
Relayhost = mailserver.isp.com.
Incoming email is pulled from the isp using fetchmail, and handed on to postfix for local delivery.
It all worked perfectly for ages, until I replaced the NAT router with a "proper" firewall-router, IPCop. IpCop standard version 1.3 with all fixes and port 113 closed off too. Also, it won't respond to pings. grc.com reports it as "Fully Stealthed". No port forwarding setups, either. Hoping I wouldn't need that.
Now the incoming email (fetchmail -> postfix thru IpCop Box) continues to work just fine. But outgoing email is stuck in the postfix outbound mail queue. The error message from the postfix maillog says "Name service error for mailserver.isp.com: Host not found, try again". This is confusing because I can ping and traceroute from the postfix mailserver to the mailserver.isp.com. The dns lookup seems to be working just fine.
Also, from LAN workstations I can send email directly to mailserver.isp.com using port 25 with Eudoras, Outlooks, etc. This is going quite happily thru the IpCop box. My preference is to route this outgoing email thru the postfix mailserver for outbound relaying, simply because its more efficient. Speeds up the LAN workstations and the postfix server can just sit there delivering email like its supposed to.
So if Outlooks and Eudoras can send email to mailserver.isp.com using port 25, why can't postfix ?
My dilemma is whether this is an IpCop or a postfix issue.
All suggestions gratefully received.
