Login or Register to Ask a Question and Join Our Community

Sharing Adsl Link

Thread Tools Search this Thread
Special Forums IP Networking Sharing Adsl Link
# 1  
Old 10-02-2007
Sharing Adsl Link

Hi guyz,

got a little bit of a situation here. we are sharing an ADSL link with
another organization. so there are 2 networks.
network 1:
has the adsl router and the whole n/w is on subnet 192.168.0.*
the adsl router has its ip as

network 2(now us):
we have set up a linux box running Centos 4.3 to act as a firewall,
proxy and dhcp + file server. our network is on subnet 192.168.1.*
the linux box has two NICS:
eth1: (varies since it takes ip dynamically from the adsl
router on n/w 1)
on our network we have a domain running on 2003 server....n our dns is
also on the 2003 machine.

from the linux box.....i can be able to surf the net, but all the
other client machines on our network (192.168.1.*) cannot access the
net. i cannot ping the adsl router or any 192.168.0* address from the
client machines, but i can do all that on the linux box.

now am suspecting i need a NAT....or a router to join the 2 networks.
however, i would like to utilize the linux box for the job (as a

Can anyone help me get through this situation....i really need to sort
this out!
or if anyone can help me get the client machines access the other
n/w.....i would be grateful...coz then i can proceed n share the link.
Login or Register to Ask a Question

Previous Thread | Next Thread

9 More Discussions You Might Find Interesting

1. IP Networking

Configuring ADSL/3G/4G connectivity with Failover and Fallback capability

Hello All, I have one requirement in which, i have 3 connections one ADSL and two 4G dongle (Jio/Airtel). Where i need to configure ADSL and 4G connections, which i have configured and able to connect internet throught them, Now i need to create set-up for failover and fall back between them,... (0 Replies)
Discussion started by: linux.amrit
0 Replies

2. Shell Programming and Scripting

Using Net::Telnet in Perl to connect to an adsl modem

Hello, First of all, congratulations on this forum! Very mice material! This is my fist thread and it has to do with connecting to an adsl modem and executing some commands. Heres what I do: $username = 'admin'; $passwd = 'admin'; $telnet = new Net::Telnet ( Timeout=>10,... (2 Replies)
Discussion started by: Ravendark
2 Replies

3. Solaris

Installing USB adsl modem?

Hello all, granted that I am an absolute beginner with Solaris, I'd like to use my adsl modem, t's a Zyxel prestige 630. I managed to install and configure it under Ubuntu using the drivers from Conexant AccessRunner ADSL USB modems with Linux ; is there a chance to do the same under Solaris 10... (0 Replies)
Discussion started by: clalfa
0 Replies

4. IP Networking

sharing of IP address for load sharing avoiding virtual server & redirection machine

I have RedHat 9.0 installed on three of my servers (PIII - 233MHz) and want that they share a common IP address so that any request made reaches each of the servers. Can anyone suggest how should I setup my LAN. I'm new to networking in Linux so please elaborate and would be thankful for a timely... (2 Replies)
Discussion started by: Rakesh Ranjan
2 Replies

5. Solaris

Solaris 10 ADSL USB modem problem

Hi, I have USB Siemens Santis 100 ADSL modem.I need driver for this modem on Solaris 10.Please help me with some info.Platform is x86.Thanks. (2 Replies)
Discussion started by: Upravnik
2 Replies

6. UNIX for Dummies Questions & Answers

Four PCs Sharing ADSL

Hello, everyone. I have a little favor to ask. Me and my friends decided sharing an ADSL line with four PCs. PC no.1: Desktop, two netcard (2000 and 8139), Mandrake 9.0 PC no.2: Acer notebook, PC Card, RTL-8139C/8139C+, MS 98 + Win 2000 Pro PC no.3: Desktop, net card 8139, WindowME + Win 2000... (1 Reply)
Discussion started by: HOUSCOUS
1 Replies

7. UNIX for Dummies Questions & Answers

ADSL with Darwin 1.41

Hey everyone, just to let you all know "I'm an uber n00b" I'm connected to Telstra Bigpond's (Australian ISP) ADSL network, now I;m running Darwin 1.41 on an Apple Macintosh PPC computer. I don't know how to set up ADSL on this system, can someone please guide me. (3 Replies)
Discussion started by: Syphor
3 Replies

8. UNIX for Dummies Questions & Answers

PPPoE + ADSL on FreeBSD 4.4

Hi everyone, This is basically my problem. I setup freebsd, and wanted to get my adsl connection up which uses pppoe to connect. I followed the steps in this (http://free.mine.nu/~squirrel/PPPoE/FreeBSD%20PPPoE%20Howto.htm) manual and configured everything successfully. The problem begins when i... (7 Replies)
Discussion started by: Luftwaffe
7 Replies

9. IP Networking

Unix and ADSL

Is ADSL support available for Unix/Linux? If I want to set up a internet server, will it have to be Windows with a seperate unix box? Or can it be a clean unix server? (2 Replies)
Discussion started by: vannie
2 Replies
Login or Register to Ask a Question
GRE(4)							   BSD Kernel Interfaces Manual 						    GRE(4)

gre -- encapsulating network device SYNOPSIS
To compile the gre device into the kernel, place the following line in the kernel configuration file: device gre Alternatively, to load the gre device as a module at boot time, place the following line in loader.conf(5): if_gre_load="YES" DESCRIPTION
The gre network interface pseudo device encapsulates datagrams into IP. These encapsulated datagrams are routed to a destination host, where they are decapsulated and further routed to their final destination. The ``tunnel'' appears to the inner datagrams as one hop. gre interfaces are dynamically created and destroyed with the ifconfig(8) create and destroy subcommands. This driver currently supports the following modes of operation: GRE encapsulation (IP protocol number 47) Encapsulated datagrams are prepended an outer datagram and a GRE header. The GRE header specifies the type of the encapsulated data- gram and thus allows for tunneling other protocols than IP like e.g. AppleTalk. GRE mode is also the default tunnel mode on Cisco routers. This is also the default mode of operation of the gre interfaces. As part of the GRE mode, gre also supports Cisco WCCP protocol, both version 1 and version 2. Since there is no reliable way to distinguish between WCCP versions, it should be configured manually using the link2 flag. If the link2 flag is not set (default), then WCCP version 1 is selected. MOBILE encapsulation (IP protocol number 55) Datagrams are encapsulated into IP, but with a shorter encapsulation. The original IP header is modified and the modifications are inserted between the so modified header and the original payload. Like gif(4), only for IP-in-IP encapsulation. The gre interfaces support a number of ioctl(2)s, such as: GRESADDRS Set the IP address of the local tunnel end. This is the source address set by or displayed by ifconfig(8) for the gre interface. GRESADDRD Set the IP address of the remote tunnel end. This is the destination address set by or displayed by ifconfig(8) for the gre interface. GREGADDRS Query the IP address that is set for the local tunnel end. This is the address the encapsulation header carries as local address (i.e., the real address of the tunnel start point). GREGADDRD Query the IP address that is set for the remote tunnel end. This is the address the encapsulated packets are sent to (i.e., the real address of the remote tunnel endpoint). GRESPROTO Set the operation mode to the specified IP protocol value. The protocol is passed to the interface in (struct ifreq)->ifr_flags. The operation mode can also be given as link0 IPPROTO_GRE -link0 IPPROTO_MOBILE to ifconfig(8). The link1 flag is not used to choose encapsulation, but to modify the internal route search for the remote tunnel endpoint, see the BUGS section below. GREGPROTO Query operation mode. GRESKEY Set the GRE key used for outgoing packets. A value of 0 disables the key option. GREGKEY Get the GRE key currently used for outgoing packets. 0 means no outgoing key. Note that the IP addresses of the tunnel endpoints may be the same as the ones defined with ifconfig(8) for the interface (as if IP is encap- sulated), but need not be, as e.g. when encapsulating AppleTalk. EXAMPLES
Configuration example: Host X-- Host A ----------------tunnel---------- Cisco D------Host E | / +------Host B----------Host C----------+ On host A (FreeBSD): route add default B ifconfig greN create ifconfig greN A D netmask 0xffffffff linkX up ifconfig greN tunnel A D route add E D On Host D (Cisco): Interface TunnelX ip unnumbered D ! e.g. address from Ethernet interface tunnel source D ! e.g. address from Ethernet interface tunnel destination A ip route C <some interface and mask> ip route A mask C ip route X mask tunnelX OR On Host D (FreeBSD): route add default C ifconfig greN create ifconfig greN D A ifconfig greN tunnel D A If all goes well, you should see packets flowing ;-) If you want to reach Host A over the tunnel (from Host D (Cisco)), then you have to have an alias on Host A for e.g. the Ethernet interface like: ifconfig <etherif> alias Y and on the Cisco: ip route Y mask tunnelX A similar setup can be used to create a link between two private networks (for example in the 192.168 subnet) over the Internet: 192.168.1.* --- Router A -------tunnel-------- Router B --- 192.168.2.* / / +------ the Internet ------+ Assuming router A has the (external) IP address A and the internal address, while router B has external address B and internal address, the following commands will configure the tunnel: On router A: ifconfig greN create ifconfig greN link1 ifconfig greN tunnel A B route add -net 192.168.2 -netmask On router B: ifconfig greN create ifconfig greN link1 ifconfig greN tunnel B A route add -net 192.168.1 -netmask Note that this is a safe situation where the link1 flag (as discussed in the BUGS section below) may (and probably should) be set. NOTES
The MTU of gre interfaces is set to 1476 by default, to match the value used by Cisco routers. If grekey is set this is lowered to 1472. This may not be an optimal value, depending on the link between the two tunnel endpoints. It can be adjusted via ifconfig(8). For correct operation, the gre device needs a route to the destination that is less specific than the one over the tunnel. (Basically, there needs to be a route to the decapsulating host that does not run over the tunnel, as this would be a loop.) If the addresses are ambiguous, doing the ifconfig tunnel step before the ifconfig(8) call to set the gre IP addresses will help to find a route outside the tunnel. In order to tell ifconfig(8) to actually mark the interface as ``up'', the keyword up must be given last on its command line. The kernel must be set to forward datagrams by setting the net.inet.ip.forwarding sysctl(8) variable to non-zero. SEE ALSO
gif(4), inet(4), ip(4), netintro(4), protocols(5), ifconfig(8), sysctl(8) A description of GRE encapsulation can be found in RFC 1701 and RFC 1702. A description of MOBILE encapsulation can be found in RFC 2004. AUTHORS
Heiko W.Rupp <hwr@pilhuhn.de> BUGS
The compute_route() code in if_gre.c toggles the last bit of the IP-address to provoke the search for a less specific route than the one directly over the tunnel to prevent loops. This is possibly not the best solution. To avoid the address munging described above, turn on the link1 flag on the ifconfig(8) command line. This implies that the GRE packet des- tination and the ifconfig remote host are not the same IP addresses, and that the GRE destination does not route over the gre interface itself. The current implementation uses the key only for outgoing packets. Incomming packets with a different key or without a key will be treated as if they would belong to this interface. RFC1701 is not fully supported, however all unsupported features have been deprecated in RFC2784. BSD
June 20, 2008 BSD

Featured Tech Videos