either that or its the switch? ever run two completely different subnets
(and networks) on the same unmanaged switch? (of course this begs the
question WHY?) but well... it has some interesting effects. of course
it works fine for each subnet within themselves but when trying to
contact one network from the other things get interesting. I did not
set this up but i walked into a client that had this type of scenario:
192.168.1.0/24 dhcp clients, servers, etc. <--> Multiple Unmanaged
10/100 switches (Linksys or something) <--> Cisco router (default gw)
<--> T1 to HQ & Internet
-and-
10.1.1.0/24 static clients <--> the same switches as above <-->
different router to another T1 to an unrelated network
the client pc's on the 10.x were pointing to the 10.x router for their
gw. neither router new anything about the other one (no static routes,
no dynamic protocols). theoretically this shouldn't really work when
trying to pass data from a PC on one subnet to a PC on the other. but
actually it does... kinda. ping worked. and it wasn't within the scope
of my work to fix this mess but I had to access one from the other and
found RDP worked like crap but for some reason VNC worked better and
allowed me to control the PCs in the second network from the first.
since this was definitely not an arp-cache thing on the PCs themselves
it had to be the switch seeing IP's and sending the data out the right
port. why some stuff worked ok and others didn't might make an
interesting point of research for the curious. of course why anyone
would want to setup networks like that is beyond me but i've always been
curious how in the heck that worked at all...
Bill Marquette wrote:
Probably those machines had 192.168.125.65's mac address still cached.
Knowing what the MAC was, they didn't need to do an arp lookup for
their default gateway to send the traffic on. Expect those machines
to stop working before too long ;-P
--Bill
On 12/9/06, Jonathan Horne <[EMAIL PROTECTED]> wrote:
i previously had 2 sites, both with pfsense firewalls.
site a - 192.168.125.0/26
site b - 192.168.125.64/26
i recently did away with site a, and since those ips were no longer
in use, i
decided to change my site b from a /26 to a /25. so i started with the
pfsense box. it ip was previously 192.168.125.65, and i changed it to
192.168.125.1. saved changes.
now, all the hosts at site b are also on the same 192.168.125.64/26,
with ips
between x.x.x.65-127. theoretically, with site a gone, they should
be able
to ping nothing below 64, since they are off their network. but, as
soon as
the pfsense interface was back up, hosts that had ips betwen
x.x.x.65-127
were already able to ping 192.168.125.1, and any other hosts on the
internet
(even tho the gateway on their network was no longer there! .65 was
unpingable).
uh, i thought i understood the basic concepts of subnetting, and if i
had it
all wrong, then why was my previous vpn between site b and a working
perfectly? or is there some devilry or trickery in the way bsd does
its tcp?
totally confused,
jonathan
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