Seeking help with multiple router setup

Archived from groups: comp.dcom.wan (More info?)

Gene wrote:

> Having trouble with multiple router setup.
>
> I have a LAN connecting 4 computers and accessing the internet through a
> router. The setup is this:
>
> The cable modem directly connects to the first router and gives it a dynamic
> IP.
>
> First router has a LAN IP of 192.168.0.1.
> It runs as a DHCP Server.
> It has Internet Port Subnet Mask of 255.255.248.0
> It has LAN Port Subnet Mask of 255.255.255.0
> It connects to 2 devices: 1 computer and a second router, both of which
> receive an IP in the range 192.168.0.2 - 192.168.0.254
>
> So the second router gets a WAN IP of 192.168.0.XXX
> and has a LAN IP of 192.168.1.1
> It has a WAN IP Subnet Mask of 255.255.255.0
> It has a LAN IP Subnet Mask of 255.255.255.0
> It has a default gateway of 192.168.0.1 (the first router)
> The other 3 computers connect to this router, and get IPs in the range
> 192.168.1.100 - 192.168.1.254
>
> Here're my problems:
>
> 1. On the Windows Network, the computer linked to the first router cannot
> see any of the computers linked to the secound router.
>
> 2. The 3 computers linked to the second router cannot keep a stable internet
> connection, and I don't think it's because of the dynamic IP assignment
> (they disconnect much more often than dynamic IP changes).
>
> One router is an old Linksys. The other is a new Netgear. Both are 4-port
> with Wireless 802.11 (b and g). Using the Netgear as the first router (i.e.
> the one directly connected to the cable modem) seems to make things worse.
> That is the setup I described above.
>
> Should the two routers have different subnet masks? Any suggestions or
> related networking info would be appreciated.
>
> Thanks,
> Gene
>
>

2 issues, two seperate causes.
As far as the PC's on the second router not being able to keep a stable
internet connection, that sounds like an issue of the "routers" (cracks
me up that linksys and netgear call their NAT boxes "routers" ) getting
confused with all the NATTING. Since all the PC's on router 2 will show
up as coming from a single IP address (as far as router 1 sees it)
router 1 will have a very hard time keeping track of the open sockets.

It's a given that the PC's connected to the first router will not see
those on the second router. Think about it - they are all natted to one
address. That is how these "routers" work - the don't actually route,
they NAT. You can't see the individual addresses on the other side, just
the routers wan address.

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Archived from groups: comp.dcom.wan,comp.protocols.tcp-ip (More info?)

(comp.protocols.tcp-ip added)

T. Sean Weintz wrote:

(snip)

> As far as the PC's on the second router not being able to keep a stable
> internet connection, that sounds like an issue of the "routers" (cracks
> me up that linksys and netgear call their NAT boxes "routers" ) getting
> confused with all the NATTING. Since all the PC's on router 2 will show
> up as coming from a single IP address (as far as router 1 sees it)
> router 1 will have a very hard time keeping track of the open sockets.

They still need to route. Anything with more than one address
needs to do some routing.

I did actually once run a NAT router such that both addresses
were on the WAN side. It then converted one destination address
to another. It seemed in that case that it did not convert the
source address, though it still worked fine for UDP. Replies
went directly to the original machine. It might be that I could
have had it convert both, but I only needed to do UDP.

-- glen

Archived from groups: comp.dcom.wan,comp.protocols.tcp-ip (More info?)

glen herrmannsfeldt wrote:


> They still need to route. Anything with more than one address
> needs to do some routing.
>
> I did actually once run a NAT router such that both addresses
> were on the WAN side. It then converted one destination address
> to another. It seemed in that case that it did not convert the
> source address, though it still worked fine for UDP. Replies
> went directly to the original machine. It might be that I could
> have had it convert both, but I only needed to do UDP.
>
> -- glen
>

Well, I guess yes. And no. Think about how a packet comes in from the
wan side - it isn't realy routed since it can only take on possible
path. It's realy being bridged with the destination address translated
- not routed. In fact some boxes even leave the original source MAC
untouched.


--
Copyright 2004 T. Sean Weintz
This post may be copied freely without
the express permission of T. Sean Weintz.
T. Sean Weintz could care less.
T. Sean Weintz is in no way responsible for
the accuracy of any information contained in
any usenet postings claiming to be from
T. Sean Weintz. Users reading postings from
T. Sean Weintz do so at their own risk.
T. Sean Weintz will in no way be liable for
premature hair loss, divorce, insanity,
world hunger, or any other adverse relults
that may arise from reading any usenet
posting attributed to T. Sean Weintz

ALSO - FWIW, The following WHOIS Record is years out of date:
Weintz, Sean (SW2893) tweintz@MAIL.IDT.NET
Sean Weintz
462 Sixth Street , #A
Brooklyn, NY 11215