I have installed Linux, and it seems to initially start booting. However it gets down to something called sendmail and then the machine seems to hang. What is happening and what should I do?
If after the install the machine seems to hang when it reaches certain processes like sendmail, apache, or SMB there is probably a network problem. The most common cause is that Linux can not look up the name of the machine you have called the box (if you set up networking to have a machine name). The machine is currently paused waiting for the network timeout of DNS lookups, and will eventually bring up the login prompt. Login in as root and check the usual culprits for a problem.
If you are directly on a network with a DNS server, make sure the file /etc/resolv.conf has the correct values for your machine's DNS server. Check with your systems administrator that the values are correct.
If you are using Linux on a network without a DNS server (or this box is going to be the DNS server), then you will need to edit the /etc/hosts file to have the hostname and IP address so that the lookups will occur correctly. The format of the /etc/hosts file is:
127.0.0.1 localhost localhost.localdomain 192.168.200.1 mymachine mymachine.mynetwork.net
Where the example machine is called mymachine.
I have upgraded to 5.x, and sendmail is no longer relaying email like it used to. What is going on?
Due to various email spammers using unknowing Red Hat boxes as email relayers and some other problems, we have turned this off by default in 5.x
You can add the names of systems that you want to be allowed to relay mail
to the file
/etc/relay_allow. The web site
http://www.informatik.uni-kiel.de/%7Eca/email/check.html for more
details on this.
If you are having problems with sites sending you UBE (Unsolicited Bulk Email), you can also deny them access to your machines with the new features of sendmail. Add the sites to the file /etc/mail/deny and then make a hash table for it.
The following command can be used to create the hash database version of this file:
makemap -v hash /etc/mail/deny < /etc/mail/deny
I have installed Linux, recompiled my kernel, and now I get errors when the network comes out about various net-pf modules not found. What is happening and what should I do?
This means that Linux was unable to find modules for various network protocols. The most common ones are net-pf-4 (IPX) and net-pf-5 (appletalk). It looks like that during a kernel recompile these were not included and some service is looking for it during the boot.
First check to see that you are not running a service that is wanting it (mars-nwe, netatalk, etc). If you are you will need to recompile the kernel with these items or turn off the service.
If you still get net-pf errors you can fix it by following these directions:
cd /etc vi conf.modules
Add the following lines to the file:
alias net-pf-3 off alias net-pf-4 off alias net-pf-5 off
This should turn off the messages upon boot as it tells linux that these are OFF and should not be looked for.