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Port Forwarding

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Posts: 16,556
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Registered: 06-04-2007

Port Forwarding

Hi

Happy New Year to all!!!

I recently asked about Port Forwarding and the informative help I received enabled me to do as I required.

But, now I am having further problems.

I only had two PCs Home Networked and wished to send Port Forwarding to one only. Now I have three PCs and want to port forward two specific ports to all three.

I have the Solewise SA130 modem and have read the info on PortForward.com

My PCs have Local IP addresses xxx.yyy.z.2, xxx.yyy.z.3 & xxx.yyy.z.4.

In order to forward, say, Port 8081 to all three should I set the Local Address From to xxx.yyy.z.2 and the Local Address To to xxx.yyy.z.4?

This seems logical to me but an not so sure. Do I need to set anything else?

Any help would be appreciated.

Cheers

Forum Moderator and Customer
Courage is resistance to fear, mastery of fear, not absence of fear - Mark Twain
He who feared he would not succeed sat still

51 REPLIES
N/A

Port Forwarding

You can only forward the port to one PC at a time.

Ian
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Posts: 16,556
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Fixes: 125
Registered: 06-04-2007

Port Forwarding

When I asked Plus Net for extra IPs I was told that port forwarding would be enough.

I am slightly confused now.

Forum Moderator and Customer
Courage is resistance to fear, mastery of fear, not absence of fear - Mark Twain
He who feared he would not succeed sat still

N/A

Port Forwarding

If you were, for example, running a http server on one machine and a smtp server on another, then port forwarding would suffice. If you wanted to run a http server on two machines, then you would need extra IP addresses, unless you configured the http server on one of the machines to use a different port.

Can you give us some more details of what you are trying to achieve?

Tim
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Port Forwarding

PN has now issued me with a block of 4 IPs but, unfortunately, the link they give for further help does not exist.

I am quite new to this and am just getting to grips with the IP addressing stuff.

They gave me IP addresses as follows:

Static IP: xxx.yyy.zzz.a Gateway Address
xxx.yyy.zzz.b address for router
xxx.yyy.zzz.c spare address
xxx.yyy.zzz.d Broadcast Address
Netmask: 255.255.255.252

I was told to turn off my router and on again and now the IP address reported by PortForward.com is the b one.

I have not changed anything in software yet on my PC but I still have complete internet access inc. email and newsgroups - so all OK there.

If I want to use an extra IP address do I simply enter the spare address xxx.yyy.zzz.c into the application's software options on my second PC and it will then use that as oposed to b as reported in port forwarding?

Also, what is meant Gateway Address and Broadcast Address?

And if I want my third PC to use yet abnother IP address do I need to ask for more from PN?

I want each machine to be able to use ports 80, 8081 and 3101 - do I need still to use port forwarding? How, if I can only forward to one PC at any time?

Sorry to sound so thick and ask so much but any help or pointers to good advice on the web would be greatly appreciated.

Cheers

Forum Moderator and Customer
Courage is resistance to fear, mastery of fear, not absence of fear - Mark Twain
He who feared he would not succeed sat still

N/A

port forwarding

I would say that you just want to open certian ports in your router's firewall, and a quick look at portforward.com for your router says that NAT rules can be assigned, one per port, with NO local address specified.

This means that all local PCs behind the firewall will recieve TCP/UDP traffic on these ports, so it is dangerous to leave enabled when you are not using them, but not sure how easy it is to enable and disable these rules on your router.

My 3com has an enable/disable check box for each rule so that you can open and close port ranges very easily depending on which applications you are using, e,g hosting games, skype etc.

Network address translation forms the basic security of your network by hiding your local PCs on a local address range behind a router that has a 'real' IP address to communicate with the internet. By default tthe router's firewall will allow HTTP traffic to communicate on port 80, 443 for SSL but secuirty is reduced by opening up other ports or putting your PCs in a DMZ with internet IP address ranges of your router. So I would make sure you are all patched up on these PCs and read up on how to lock them down for maximum security if this is what you are trying to achieve.

BTW Gateway address is the router's address that will foward local address IP on to other networks, i.e. the internet, and broadcast address is dependent on your subnet configuration, but would typically be something like 192.168.1.255 for a local subnet (255 indicating broadcast, and can't be assigned to a PC address) . this is used to limit traffic by sending brodacasts only within subnets, rahter than across the whole network.

hope this helps
N/A

Port Forwarding

You will need to configure your router so that you can have both private and public IP addresses on your LAN, and then use the spare public IP address you have been given for one of your machines.

Tim
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Port Forwarding

I have read as much as I can on Port Forwarding and IP addresses and feel flumoxed by it all.

The three PCs I have use the default gateway k.l.m.1
and each Pc has been given the internal Network IP addresses in the range k.l.m.2 to k.l.m.3

I now have the default external IP address of xxx.yyy.zzz.a with spare address of xxx.yyy.zzz.b

I want port 8081 to go to PC k.l.m.3 using External IP xxx.yyy.zzz.a and port 8082 tpo go to PC k.l.m.4 using external IP xxx.yyy.zzz.b

I then want port 3031 to go to both PCs.

On Portforwrd.com I read that there could be a confict because I have assigned my network PCs in the rang of 2 to 4 and the DHCP could also assign these addresses but in the order the PCs were switched on thereby posibly causing the conflict.

WOuld I be better assigning my network PCs in the range of, say, 152, to 154?

Please help me in my quest as I am beginning to lose my hair.

Thanks

Forum Moderator and Customer
Courage is resistance to fear, mastery of fear, not absence of fear - Mark Twain
He who feared he would not succeed sat still

N/A

Port Forwarding

It is impossible to use port forwarding to forward the same port to more than one private IP address. You will have to give one of your machines a public IP address, and you then do not need to use port forwarding for this machine.

Tim
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Port Forwarding

Thanks for the advice.

With a public IP address can it still be part of my home Network?

I assume that as I am not changing the Network name there should be no problem and that all I need to do is go to Internet Protocol (TCP/IP) Properties and change the IP Address there from the internal one I set to the public (external) extyra IP given by PN.

But do I leave the gateway address as it was or change it to the nee Gateway Address given with the block of IPs as described above.

I am still using the same router as before so I think the former but maybe I am wrong.

Thanks again for advice.

Forum Moderator and Customer
Courage is resistance to fear, mastery of fear, not absence of fear - Mark Twain
He who feared he would not succeed sat still

N/A

Port Forwarding

The gateway IP address would be the public IP address of your router. As I said earlier, you will need to configure your router so that you can have one machine on your LAN with a public IP address and the rest with private IP addresses.

Can you tell us what application you want to run on these machines, as you may be unnecessarily complicating things?

Tim
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Posts: 16,556
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Registered: 06-04-2007

Port Forwarding

Hi Tim

Sorry for the long wait for reply but needed to recover from the New Year celebrations Wink

I want to run a couple of Web Cam servers and, soon, have another set up for security so that I can view from abroad or whereever I happen to be.

I have been reading the Solwise SA130 Installation Manual but I am somewhat perplexed by it all. Is there a step-by-step guide for setting up a Network of 3 PCs - two private and one public - on the internet which would help me acheive my gaols?

Any help you can offer would be appreciated but I feel that extra reading would come in handy so that I begin to understand what it is I am doing.

Cheers

Forum Moderator and Customer
Courage is resistance to fear, mastery of fear, not absence of fear - Mark Twain
He who feared he would not succeed sat still

Community Veteran
Posts: 14,469
Registered: 30-07-2007

Port Forwarding

The problem you are in is you are trying to use the router in both NAT and non-NAT mode: non-nat to allow through your extra PlusNet IP and NAT to use DHCP to assign a local IP (192.168.X.X) to your other PCs and expecting the router to NAT you local IP to your PlusNet IP.

To do this is a bit tricky on the SAR130. See if the following helps which appears to be trying to do something similar to you:

http://www.solwiseforum.co.uk/archive/index.php?t-5314.html
Moderator
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Posts: 16,556
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Registered: 06-04-2007

Port Forwarding

Hi Peter.

Thanks for the pointer - sadly a lot of this is techno-babble to me as I am still learning.

I have read before that I need to use NAT & No-NAT on the SA130 but would really like some pointers to how to understand what this means as well as set it up.

To re-iterate again what I am trying to do:

Three PCs on one Network with two using the router IP from the new block of 4 allocated by PN and the third PC using the spare IP.

My understanding of this is that I would still need to use port-forwarding for the 2nd PC on the router IP but would not need to use port-forwarding for the PC with the spare IP.

Thanks agian for any help offered.

Cheers

Forum Moderator and Customer
Courage is resistance to fear, mastery of fear, not absence of fear - Mark Twain
He who feared he would not succeed sat still

N/A

Port Forwarding

Assuming your SAR130 is already configured in natted mode, do the following (backup your configuration first!):

[list=1]
  • Connect to the web interface of the SAR130
  • Check your WAN IP address on the Home tab
  • On the Services tab click on NAT and disable NAT
  • Go to the LAN tab and change your LAN IP address to the one you have just seen as your WAN address, subnet mask 255.255.255.252 (you must submit this twice)
  • Connect to the telnet interface of the SAR130
  • Type commit to save the changes
  • Type delete ppp intf ifname ppp-0
  • Type create ppp intf ifname ppp-0 ppoa lowif aal5-0 numif eth-0 droute true
  • Type create ethernet intf ifname veth-0 ip 192.168.7.1 mask 255.255.255.0
  • Type create nat rule entry ruleid 1 napt lcladdrfrom 192.168.7.2 lcladdrto 192.168.7.254
  • Type modify nat global enable
  • Type commit
    [/listShocked]

    You can now give one of your PCs the spare public IP address, and the other two PCs a private IP address in the range 192.168.7.2 to 192.168.7.254.

    Tim