Re: Binding inetd to ip

From: Borbely Zoltan (bozoat_private)
Date: Wed Jan 26 2000 - 16:44:04 PST

  • Next message: Mikes Roman: "RE: SSL"

    Hello,
    
    On Tue, Jan 25, 2000 at 11:22:23AM -0500, Nicholas Tang wrote:
    > Is it possible to bind inetd to a specific ip address/ethernet card under
    > linux?  I haven't been able to find any info myself, but the reason I
    > ask is because I currently am running a nameserver that has two network
    > cards.
    
    No, the standard inetd can't do that. You have to use xinetd. If you use
    xinetd, you can specify the listen address for every service.
    
    > I bound ssh to the first card and am running xntpd on there as well (does
    > that have to actually bind to a port?  Is there any way to stop that?  If
    > not is there any way to at least limit it to one card/ip?  Would I be
    > better off just running ntpdate once an hour?) and then I'm running
    > Portsentry on the box to watch for any suspicious activity.
    
    You can't restrict xntpd to bind to every interface. You have to configure
    the kernel packet filter with ipchains.
    
    > Here's how a netstat -na looks:
    > 
    > [root@thisbox /root]# netstat -na
    > Active Internet connections (servers and established)
    > Proto Recv-Q Send-Q Local Address           Foreign Address         State      
    > tcp        0      0 199.2.242.x:22        199.2.242.z:1092	ESTABLISHED 
    > tcp        0      0 199.2.242.x:22        0.0.0.0:*               LISTEN      
    > tcp        0      0 199.2.242.y:53        0.0.0.0:*               LISTEN      
    > udp        0      0 199.2.242.y:123       0.0.0.0:*                           
    > udp        0      0 199.2.242.x:123       0.0.0.0:*                           
    > udp        0      0 127.0.0.1:123           0.0.0.0:*                           
    > udp        0      0 0.0.0.0:123             0.0.0.0:*                           
    > udp        0    304 0.0.0.0:1024            0.0.0.0:*                           
    > udp        0      0 199.2.242.y:53        0.0.0.0:*                           
    > raw        0      0 0.0.0.0:17              0.0.0.0:*               7           
    > raw        0      0 0.0.0.0:6               0.0.0.0:*               7           
    > raw        0      0 0.0.0.0:1               0.0.0.0:*               7           
    > raw        0      0 0.0.0.0:6               0.0.0.0:*               7           
    > Active UNIX domain sockets (servers and established)
    > Proto RefCnt Flags       Type       State         I-Node Path
    > unix  0      [ ACC ]     STREAM     LISTENING     456    /dev/gpmctl
    > unix  0      [ ACC ]     STREAM     LISTENING     364    /var/run/ndc
    > unix  4      [ ]         DGRAM                    299    /dev/log
    > unix  1      [ ]         DGRAM                    301
    > /var/named/dev/log
    > unix  0      [ ]         DGRAM                    2558   
    > unix  0      [ ]         DGRAM                    467    
    > unix  0      [ ]         DGRAM                    410    
    > unix  0      [ ]         DGRAM                    362    
    > unix  0      [ ]         DGRAM                    315    
    > [root@thisbox /root]# 
    > 
    > Any ideas on anything else I can clean up?  Also, I don't mean to sound
    > ignorant but anyone have any idea what's listening on 1024, 1, 6 ,and
    > 17?  It's a Redhat 6.0 box, if that helps.
    
    1024/udp maybe the query address of the bind. Try ``netstat -nap'' or ``lsof'',
    these utilities write the name of the programs holding sockets. In this
    case you can use ``fuser -n udp 1024'' to get the process id holding this
    socket.
    
    Zoltan BORBELY
    



    This archive was generated by hypermail 2b30 : Fri Apr 13 2001 - 13:59:27 PDT