DHCP Server

pedantic · 15-06-2004, 15:33

Hi

I wonder if some of you technically minded people can answer a question

I've just inspected the info when using the winipcfg tool and there is something strange. When I first set up my firewall rules I put in the DHCP address to permit it to connect to my machine. I've noticed now though, that the address is different to the one I have in my rule sets.

Question 1 : Is there anything I should be worried about here ?

Question 2 : Do I need to make another rule to allow this server to connect to my machine ?

Question 3 : By not allowing this new server address at the moment, should I be noticing any problems, such as my browsing speed being hit and miss at the moment, or is that just down to the temperamental proxy servers ?

Regards

imback · 15-06-2004, 15:42

Do you mean you Ip address has changed since you first installed? If so and you are using NTL (or any other ISP that uses a dynamic IP address) then this will happen.

Your IP will normally stay the same even after being re newed but sometimes, due to one circumstance or another, it will change.

pedantic · 15-06-2004, 15:45

Hi

No, not my ip address, the ip address of the DHCP server itself.

Regards

AdeRickus · 15-06-2004, 18:15

Hmmm,

You mean you have a software firewall I presume ??

And you have allowed your PC ( via said firewall program ) to talk to a DHCP server of a specific IP address ??

Is this correct ??

pedantic · 15-06-2004, 18:24

Hi

Yes, I have allowed a DHCP server from a specific ip address to (talk) to my machine through a software firewall. But the ip address of the DHCP server has changed since I originally configured the rule in my firewall.

AdeRickus · 15-06-2004, 18:32

Hmmm,

In theory if the DHCP server from NTL has changed address and it tries to issue another address you should not be able to peruse the web, however, both would have to be true for this to happen.

Make sure the IP that you are trying to DHCP from, is an IP of an NTL server. If so allow the DHCP, although if the NTL gurus out there can confirm or deny I would not have thought for this exact reason, that there are not many DHCP servers that are accessible by you or the DHCP servers do not change IP addresses very often,

As long as your IP is valid for you it should not affect browsing speeds, if the IP is not valid for you you should not be able to browse ( this, to be fair should not happen anyway ).

pedantic · 15-06-2004, 18:42

As far as I'm aware, ntl's DHCP server addresses are private addresses (somebody correct me if I'm wrong on that point) so how do I check if it's an ntl address or not ? It is very strange though, that an address that I have not specified as having access to my machine can still get through (maybe there is a more technical reason for this and I'd love an explanation from anyone) possibly something to do with routing

Regards

ian@huth · 15-06-2004, 18:43

Have a read of Robin Walkers site at http://homepage.ntlworld.com/robin.d...dr.html#dhcpip

AdeRickus · 15-06-2004, 18:43

Whats the IP ?

pedantic · 15-06-2004, 18:46

Quote:

Originally Posted by ianathuth

Have a read of Robin Walkers site at http://homepage.ntlworld.com/robin.d...dr.html#dhcpip

Hi

I've already read that article, but it doesn't help me in wondering why it has changed from the original address to a different one.

Regards

AdeRickus · 15-06-2004, 18:48

What are the 2 IP's ??

pedantic · 15-06-2004, 18:48

Quote:

Originally Posted by AdeRickus

Whats the IP ?

The newly discovered ip is 10.185.16.134 although I can't say how long it has been changed for, as I've only just discovered it.

Regards

ian@huth · 15-06-2004, 18:51

Quote:

Originally Posted by pedantic

Hi

I've already read that article, but it doesn't help me in wondering why it has changed from the original address to a different one.

Regards

Did you read the bit about NTL having two DHCP servers per region and how to find the IP address of the second one?

greencreeper · 15-06-2004, 18:53

I would expect that as NTL upgrades and reconfigures the infrastructure some IP addresses will change. Once a week I check all the IPs (UBR, DHCP...) just to make sure nothing has changed and if it has, I update my firewall (ZA Pro). I also guess that as a machine goes searching for a DHCP server to provide it with an IP address, it might not always find the same server. Dunno.

pedantic · 15-06-2004, 18:55

Quote:

Originally Posted by ianathuth

Did you read the bit about NTL having two DHCP servers per region and how to find the IP address of the second one?

Hi

Yes, sorry I should have mentioned that earlier, I have rules for both DHCP servers in my ruleset. This new one is different to both of the original ones though.

Regards