# Postfix: fatal: unknown service: smtp/tcp

## ericdes

I'm not sure how I got into that   :Crying or Very sad:  . I don't remember having changed much in my email server configuration. Here's what I do:

This server just tells Postfix to send emails through a relay at this address 10.0.0.3 (It's another DomU server that does all the email work, Postfix, Amavis, Spamassassin...)

So my setup for this server (at 10.0.0.1) is very simple:

```

relayhost = [10.0.0.3]

```

Since yesterday I've gotten those messages, and email hasn't been delivered...

 *Quote:*   

> 
> 
> Aug 23 07:12:04 es01 postfix/smtp[6788]: smtp_parse_destination: [10.0.0.3] smtp
> 
> Aug 23 07:12:04 es01 postfix/smtp[6788]: fatal: unknown service: smtp/tcp
> ...

 

I'm wondering why it goes through smtp, shouldn't it just pass the email to 10.0.0.3? Nothing has been configured as chrooted in master.cf, what does the private in private/smtp mean?

I'm not sure what I should do from there? Any help?

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## Ijon Tichy

Odd. That log line--

 *Quote:*   

> fatal: unknown service: smtp/tcp

 

Is usually an indication that your master.cf file is set up for chrooting the SMTP client, but the chroot environment isn't fully set up (Postfix FAQ "What does "fatal: unknown service: smtp/tcp" mean?). 

Perhaps giving us a look at your master.cf file would help shed some light on things.

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## ericdes

Every line is marked with n in the chroot column. How can I check otherwise if Postfix is running chrooted?

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## kashani

what happens when you remove the square brackets around the ip address and restart your Postfix?

kashani

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## ericdes

I changed to this

```

relayhost = [10.0.0.3]:25

```

and it worked!!!

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## .:chrome:.

check your /etc/services file

postfix can read it?

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## ericdes

/etc/services is read-write by root only. Postfix is running with username postfix.

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## yottabit

Thanks for this thread! I found that my /etc/services was set to root:root rw-/r--/---. I just gave other 'r' access and Postfix works now..

So this begs the question... how did this just start happening after years of use without changing my Postfix configuration? I did not upgrade Postfix, so it must have been a Gentoo layout or system file change?

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## .:chrome:.

 *ericdes wrote:*   

> /etc/services is read-write by root only. Postfix is running with username postfix.

 

/etc/services must to be readable from ALL users

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