Christopher Sawtell wrote:
Short:
Because you cannot mix ( simply ) networks like that.
The netmask 255.255.255.0 is 24 bits long which limits you to 256
addresses, i.e. 254 machines, plus a broadcast address and a network
address.
Just a quick factual improvement. It's actually a limitation of 255
addresses with 253 usable because 0 and 255 are special. 0 represents
the network but has no practical use, 255 is the broadcast address,
which is used when trying to find the MAC address of other hosts.
Yeah, either go for a /16 netmask OR change the 5 to a 1 in the third
octet. Actually, you shouldn't have to worry about the DHCP server
issuing a duplicate address, because (1) some DHCP servers detect an
existing address and so won't issue it and (2) most clients use
Gratuitous-ARP to check that the address they have been issued is not a
duplicate.
Michael.
I do not know the intimate details of the DHCP server you have there,
but if you could persuade it to allow for a larger network, i.e. in
your case, a 21 bit mask - 255.255.128.0 - then you could have your
server on 192.168.1.201 and the rest of the dynamically assigned hosts
on 192.168.5.x
Be sure to allocate an appropriate broadcast address. It's usually the
last, or highest numbered, address available in the network.
It would help considerably if you could let us know exactly what the
satellite modem is, and the URL of its documentation.
Long:
You need to read up on the details of IP network addressing and routing.
Probably one of the best is the appropriate chapter in the RUTE book
by Paul Sheer.
http://rute.2038bug.com/node28.html.gz
Note that the're gzip compressed files, and thus won't work with I.E.,
but are fine with Mozilla Firefox, and derivatives. Konqueror is ok
too.
Googling with the search term "rusty russell internet tutorial" will
yield a number of good pages of advanced know-how, but imho Paul
Sheer's prose is much easier to understand.
2008/10/5 David Lowe <[EMAIL PROTECTED]>:
Hello cluggers, hope someone can take 5 minutes to give me a hand...
I've just installed a two-way satellite modem (because I live way out in the
styx and can't get anything else). It includes a DHCP server which I decided
to start using; previously everything was static. But I have one machine (my
MythTV server) that really needs to keep its static IP address. I have
worked out how to 'reserve' it's address on the DHCP server by specifying
it's MAC address. I'm not certain it works yet but that's not my problem...
My problem is that the DHCP server hands out addresses in the range
192.168.5.11/254. It's Ethernet interface is 192.168.5.100/255.255.255.0.
But I want to leave my server with a static address of 192.168.1.201 (its
easier to leave it alone rather than have to shag around with mySQL issues).
The result is that the server disappears off the network. I guess it's the
'5' in the IP address that's causing the problem... but from my limited
understanding, I thought internal address were internal and it should not
matter.
I guess I can work around the problem by either reconfiguring (or disabling)
the DHCP server (but not sure if I might stuff anything else up) or the
server (don't really want to face the drama of changing the host of a MythTV
server) - so I thought I would ask first: why can't I mix IP addresses like
this?
tia
- David
