xymon client init.d script

#!/sbin/sh
#
case "$1" in
start)
        [ -f /opt/cmtools/xymon/client/runclient.sh ] || exit 0
        su - cmuser  -c "/opt/cmtools/xymon/client/runclient.sh start --hostname=cmssbea10.my.domain"
        ;;
stop)
        su - cmuser -c "/opt/cmtools/xymon/client/runclient.sh stop --hostname=cmssbea10.my.domain"
        ;;
*)
        echo "Usage: $0 { start | stop }"
        exit 1
        ;;
esac
exit 0

Configure iptables (firewall) in Fedora

Basic Setup:

Here I have mentioned the basic configurations for enabling iptables in fedora linux.

List your current iptables configuration.:

[root@cmlin02:~]# iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     all  --  anywhere             anywhere            state RELATED,ESTABLISHED 
ACCEPT     icmp --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     tcp  --  anywhere             anywhere            state NEW tcp dpt:http 
ACCEPT     tcp  --  anywhere             anywhere            state NEW tcp dpt:bb 
ACCEPT     tcp  --  anywhere             anywhere            state NEW tcp dpt:ssh 
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:snmp 
ACCEPT     udp  --  anywhere             anywhere            udp dpt:snmp 
ACCEPT     udp  --  anywhere             anywhere            udp dpt:netbios-ns 
ACCEPT     udp  --  anywhere             anywhere            udp dpt:netbios-dgm 
ACCEPT     tcp  --  anywhere             anywhere            state NEW tcp dpt:netbios-ssn 
ACCEPT     tcp  --  anywhere             anywhere            state NEW tcp dpt:microsoft-ds 
ACCEPT     tcp  --  anywhere             anywhere            state NEW tcp dpt:https 
ACCEPT     udp  --  anywhere             anywhere            udp dpt:domain 
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:domain 
ACCEPT     tcp  --  anywhere             anywhere            state NEW tcp dpt:ldap 
ACCEPT     tcp  --  anywhere             anywhere            state NEW tcp dpt:ldaps 
ACCEPT     tcp  --  anywhere             anywhere            state NEW tcp dpt:ndmp 
REJECT     all  --  anywhere             anywhere            reject-with icmp-host-prohibited 
ACCEPT     udp  --  anywhere             anywhere            state NEW udp dpt:49222 
ACCEPT     udp  --  anywhere             anywhere            state NEW udp dpt:mdns 

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         
REJECT     all  --  anywhere             anywhere            reject-with icmp-host-prohibited 

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         

1) To allow established sessions to receive traffic

# iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT 

2) You could start by blocking traffic, but you might be working over SSH, where you would need to allow SSH before blocking everything else.

To allow incoming traffic on the default ssh port (22)

# iptables -A INPUT -p tcp --dport 22 -j ACCEPT

To allow incoming traffic on the default Squid port (3128)

# iptables -A INPUT -p tcp --dport 3128 -j ACCEPT

To allow incoming traffic on the default Apache port

# iptables -A INPUT -p tcp --dport 80 -j ACCEPT

To allow incoming traffic on the default samba port

# iptables -A INPUT -p udp --dport 137 -j ACCEPT
# iptables -A INPUT -p udp --dport 138 -j ACCEPT
# iptables -A INPUT -p udp --dport 139 -j ACCEPT 
# iptables -A INPUT -p tcp --dport 139 -j ACCEPT
# iptables -A INPUT -p tcp --dport 445 -j ACCEPT   

To allow incoming traffic on the default SNMP port (161)

# iptables -A INPUT -p tcp --dport 161 -j ACCEPT
# iptables -A INPUT -p udp --dport 161 -j ACCEPT 

Now check the current configuration

[root@cmlin02:~]# iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination
ACCEPT     all  --  anywhere             anywhere            state RELATED,ESTABLISHED
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:http
ACCEPT     tcp  --  anywhere             anywhere            udp dpt:netbios-ns
ACCEPT     tcp  --  anywhere             anywhere            udp dpt:netbios-dgm
ACCEPT     tcp  --  anywhere             anywhere            udp dpt:netbios-ssn
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:netbios-ssn
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:snmp
ACCEPT     tcp  --  anywhere             anywhere            udp dpt:snmp
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:microsoft-ds 
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:squid

3) Once we enabled the above port.we can drop all other incoming ports.

# iptables -A INPUT -j DROP

Now check the rule

# iptables -L

For Interface based access for eth0 specify -i eth0

4) In the final step we have to enable loopback interface. After all the traffic has been dropped. We need to insert this rule before that. Since this is a lot of traffic, we’ll insert it as the first rule so it’s processed first.

#iptables -I INPUT 1 -i lo -j ACCEPT

5) To enabling logging

# iptables -I INPUT 5 -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7 

6) To save this configuration

# iptables-save >  /etc/sysconfig/iptables

or

#service iptables save  
#service iptables start

This configuration will enable ssh port and disable all other incoming ports.
To manually edit iptables config
Also you can manual edit /etc/sysconfig/iptables

IP Tables configuration for other Services

1) Iptables for default ldap port

# iptables -A INPUT -p tcp --dport 389 -j ACCEPT
# iptables -A INPUT -p tcp --dport 636 -j ACCEPT

or manually edit /etc/sysconfig/iptables and add the below mentioned line

-A INPUT -p tcp -m tcp --dport  389 -j ACCEPT 

2) Iptables for Backup Exec

3) IP tables for smtp

 #iptables -A INPUT -p tcp --dport 25 -j ACCEPT

or manually edit /etc/sysconfig/iptables and add the below mentioned line

-A INPUT -p tcp -m tcp --dport  25 -j ACCEPT 

4) iptables for smtps

 #iptables -A INPUT -p tcp --dport 465 -j ACCEPT
 

or manually edit /etc/sysconfig/iptables and add the below mentioned line

-A INPUT -p tcp -m tcp --dport  465 -j ACCEPT 

5) iptables for pop3 , pop3s

 #iptables -A INPUT -p tcp --dport 110 -j ACCEPT
 #iptables -A INPUT -p tcp --dport 995 -j ACCEPT

or manually edit /etc/sysconfig/iptables and add the below mentioned line

-A INPUT -p tcp -m tcp --dport  110 -j ACCEPT 
-A INPUT -p tcp -m tcp --dport  995 -j ACCEPT 

6) iptables for imap , imaps

 #iptables -A INPUT -p tcp --dport 143 -j ACCEPT
 #iptables -A INPUT -p tcp --dport 993 -j ACCEPT  

or manually edit /etc/sysconfig/iptables and add the below mentioned line

-A INPUT -p tcp -m tcp --dport  143 -j ACCEPT 
-A INPUT -p tcp -m tcp --dport  993 -j ACCEPT 

7) iptables for webmin default port

 #iptables -A INPUT -p tcp --dport 10000 -j ACCEPT

or manually edit /etc/sysconfig/iptables and add the below mentioned line

-A INPUT -p tcp -m tcp --dport  1000 -j ACCEPT 

8) IPtables for named, domain

 #iptables -A INPUT -p tcp --dport 53 -j ACCEPT
 #iptables -A INPUT -p udp --dport 53 -j ACCEPT 

or manually edit /etc/sysconfig/iptables and add the below mentioned line

-A INPUT -p tcp -m tcp --dport  53 -j ACCEPT 
-A INPUT -p udp -m udp --dport  53 -j ACCEPT 

9) iptables for TFTP server

 #iptables -A INPUT -p udp --dport 69 -j ACCEPT 

or manually edit /etc/sysconfig/iptables and add the below mentioned line

-A INPUT -p udp -m udp --dport  69 -j ACCEPT 

10) iptable configuration for DHCP server

 #iptables -A INPUT -p udp --dport 67 -j ACCEPT 
 #iptables -A INPUT -p udp --dport 68 -j ACCEPT  

or manually edit /etc/sysconfig/iptables and add the below mentioned line

-A INPUT -p udp -m udp --dport  67 -j ACCEPT 
-A INPUT -p udp -m udp --dport  68 -j ACCEPT 

11) iptables for NFS server- click here

12) iptables for FTP server – click here

13) iptables for NTP server

 #iptables -A INPUT -p udp --dport 123 -j ACCEPT 

or manually edit /etc/sysconfig/iptables and add the below mentioned line

-A INPUT -p udp -m udp --dport  123 -j ACCEPT 

One of my iptables files:

[root@cmlin02:~]# more /etc/sysconfig/iptables
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [85:9266]
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT 
-A INPUT -p icmp -j ACCEPT 
-A INPUT -i lo -j ACCEPT 
# HTTP
-A INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT
# XYMON
#-A INPUT -p tcp --destination-port 80 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 1984 -j ACCEPT
# SSH
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
# SNMP
-A INPUT -p tcp --dport 161 -j ACCEPT
-A INPUT -p udp --dport 161 -j ACCEPT
# SAMBA
-A INPUT -p udp -m udp --dport 137 -j ACCEPT
-A INPUT -p udp -m udp --dport 138 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 139 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 445 -j ACCEPT
# HTTPS
-A INPUT -p tcp -m state --state NEW --dport 443 -j ACCEPT
# BIND
-A INPUT -p udp -m udp --dport 53 -j ACCEPT
-A INPUT -p tcp --dport 53 -j ACCEPT
# LDAP
-A INPUT -m state --state NEW -m tcp -p tcp --dport 389 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 636 -j ACCEPT
# WEBMIN
-A INPUT -m state --state NEW -m tcp -p tcp --dport 10000 -j ACCEPT

#-A INPUT -p tcp -m tcp --dport 3306 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited 
-A FORWARD -j REJECT --reject-with icmp-host-prohibited 

# avahi
-A INPUT -m state --state NEW -p udp --dport 49222 -j ACCEPT
-A INPUT -m state --state NEW -p udp --dport 5353 -j ACCEPT
COMMIT

Managing Linux Services

Red Hat / CentOS

  1. Display all the available services
    /sbin/chkconfig --list
  2. Enable the service
    /sbin/chkconfig [name] on
  3. Disable the service
    /sbin/chkconfig [name] off
  4. Start the background service
    /sbin/service [name] start
  5. Stop the background service
    /sbin/service [name] stop
  6. Restart the background service
    /sbin/service [name] restart
  7. Display the background service status
    /sbin/service [name] status

Ubuntu

  1. Display all the available services
    N/A
  2. Enable the service
    /usr/sbin/update-rc.d [name] defaults
  3. Disable the service
    /usr/sbin/update-rc.d -f [name] remove
  4. Start the background service
    /usr/sbin/service [name] start
  5. Stop the background service
    /usr/sbin/service [name] stop
  6. Restart the background service
    /usr/sbin/service [name] restart
  7. Display the background service status
    /usr/sbin/service [name] status