Can't see the outside world?

ccgorman

Our internal web server seems not to be able to access files from outside itself. What I mean by this is when I run the php function:

file("http://www.phpbuilder.com/); //any URL is the same

The internal server can not access that file.

Nor can our internal server send mail anymore, i.e. using the mail() function. I think this is related because this as well would require sending information outside our network.

It is an Apache webserver, running PHP and MySQL. (all most recent versions).

Any ideas on why our server is not able to see the outside world? Is there any new security features that have been installed requiring me to update files?

Thanks,
Chris

tsinka

Hi,

check if allow_url_fopen = On is set in your php.ini.
The mail problem might be a configuration issue. Which OS do you use and which mail app (e.g. sendmail) ?

ccgorman

We are using sendmail and a Linux OS.

tsinka

Ok,

configuring sendmail might be some kind of tricky. The default behaviour of sendmail is to use the complete hostname as domain name for sending out mails. If the host name is e.g. ourserver.ourdomain.com and that host isn't resolveable externally then most mail servers would not accept the mail for delivery.

To get around that problem you have to make sendmail to use your main domain.

Check your sendmail.cf (in most cases located in /etc) and change the following part:

who I masquerade as (null for no masquerading) (see also $=M)

DMmydomain.com

That's the first thing to do.

Second you might want to change the genericstable to map the web server user's mail address to an official mail address.

Edit the /etc/mail/genericstable and add the following line (assuming that the web server runs as wwwrun):

wwwrun info@mydomain.com

Change the mail address to the right to your needs.

Then create a new genericstable db with:

makemap hash genericstable.db < genericstable

and restart sendmail. In our case that solved the problem 🙂

Were you able to solve the url fopen problem ? Can you ping or resolve outside hosts generally on the linux box ?

Regards,
Thomas

tsinka

I forgot one thing:

In the genericstable file you must use tabs between the username and the mail address, don't use white spaces 🙂

Thomas

ccgorman

check if allow_url_fopen = On is set in your php.ini.
Yes this is set to 1, which is the same as on I guess.

I tried to ping an outside host and got a name lookup failure.

Not sure what is going on, but I will try to configure sendmail today anyway.

-Chris

tsinka

Ok,

most likely resolv.conf isn't set up correctly. Check your resolv.conf, here's an example:

search mydomain.com
nameserver ns1.mydomain.com
nameserver ns2.mydomain.com

Also make sure that the default gateway is set on that server.

Thomas

ccgorman

Excellent, thanks a lot that seemed to fix it, I haven't been able to test sendmail yet, but I think this fix will sort that as well. Strange thing happened. I can't seem to ftp into the internal server anymore, so I am just trying to figure out what caused this. Would it have anything to do with modifying the resolv.conf file?

tsinka

Hard to imagine without any more info 🙂

But I think the best point to start at is to check if the ftp service is enabled in the inetd.conf and if the inetd service is running at all. Besides that I'd suggest to check the log files in /var/log for any messages regarding denied ftp access.

Thomas