Re: UCARP Behind NAT
Any ideas where a good place to ask for help on this topic is? Is
there a UCARP mailing list? I realize it might be a little specific
for this list.
Thanks,
Chris
On Sun, Nov 13, 2011 at 8:13 PM, Chris Snyder <chris@keyedupmedia.com> wrote:
> Hey Guys,
>
> First time here on the list, so hopefully I get everything right here.
>
> I have two Squeeze systems that I have setup with UCARP for auto-failover.
>
> Here's the relevant /etc/network/interfaces of Server 1:
>
> 10 iface eth0 inet static
> 11 address 192.168.1.21
> 12 netmask 255.255.255.0
> 13 gateway 192.168.1.1
> 14 dns-nameservers 8.8.8.8 8.8.4.4
> 15
> 16 # UCARP
> 17 ucarp-vid 3
> 18 ucarp-vip 192.168.1.20
> 19 ucarp-password [pass-here]
> 20 ucarp-advskew 100
> 21 ucarp-advbase 1
> 22 ucarp-master no
> 23
> 24
> 25 iface eth0:ucarp inet static
> 26 address 192.168.1.20
> 27 netmask 255.255.255.255
>
>
> And /etc/network/interfaces of Server 2:
>
>
> 10 iface eth0 inet static
> 11 address 192.168.1.22
> 12 netmask 255.255.255.0
> 13 gateway 192.168.1.1
> 14 dns-nameservers 8.8.8.8 8.8.4.4
> 15
> 16 # UCARP
> 17 ucarp-vid 3
> 18 ucarp-vip 192.168.1.20
> 19 ucarp-password [pass-here]
> 20 ucarp-advskew 100
> 21 ucarp-advbase 1
> 22 ucarp-master no
> 23
> 24 iface eth0:ucarp inet static
> 25 address 192.168.1.20
> 26 netmask 255.255.255.255
>
> Now this setup works great on the LAN. I can access 192.168.1.20 fine
> while pulling the Ethernet cables from either server. The problem is
> that I'm trying to forward an external IP to 192.168.1.20 through a
> NAT.
>
> It forwards fine when both machines first come up and Server 1 is
> dominant. I can ping 192.168.1.20 and all is well. I can ping the
> external IP and all is well. Then if I pull the cable on Server 1,
> Server 2 picks up fine -- I can ping 192.168.1.20 and all is well.
> However the external IP does not forward to 192.168.1.20. It acts as
> if the forward is non-existent for Server 2. If I plug Server 1 back
> in and unplug Server 2 so Server 1 takes back over, the external IP
> forwards again.
>
> I'm thinking this has something to do with UCARP's multicast. There is
> traffic to a multicasted IP of 224.0.0.18. Is it possible this router
> (Kentrox q2300) is having trouble with this multicasted IP address?
>
> I guess I'm just looking for ways to troubleshoot where the problem
> with this is. What gets me is that the LAN IP works great in all
> regards, it's just the forwarding of the external IP address is
> problematic. How can I get UCARP to use a broadcasted address rather
> than multicasted one so I can try that?
>
> Thanks guys,
> Chris
>
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