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1811 multiple IP config question

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  • 1811 multiple IP config question

    Right now I have another router configured that keeps crashing in the middle of the day. We bought an 1811 to replace it.

    Right now I have the old router (also cisco) configured doing NAT overload on 205.x.x.130 on fa 0. Fa1 is the internal interface and was given an ip of I'm doing forwarding for email and voip to IPs on the 192.168.10.x network. The problem is, after doing some packet sniffing, I've determined that NAT is causing the occasional dropped call for our voip. One side of a conversation will go dead but the other side stays active so one person thinks they're on hold and the other side hears dead air. wireshark shows that the RTP stream stops because the port it was using becomes unreachable. This happens < 1% of all calls, but it's an issue because we do a large volume of calls.

    Anyway, I had no problems setting up NAT overload and port forwarding, but i'm having a hell of a time trying to assign multiple public ip addresses to individual devices on the network with the 1811.

    I'm doing

    for Fa 0:
    ip address 205.x.x.130
    ip route Fa 0
    ip default-gateway 205.x.x.129

    Now the 1811 has a switch built-in to it with interfaces fa 2-9 on vlan 1 by default. I plug my voip server into it and give it an ip of 205.x.x.131 and it doesn't work. I've tried various static routes pointing at the directly connected interfaces to no avail.

    In the past, with switches that weren't integrated with the router i've run a cable from the internal router interface to the switch and then I was able to give devices on the switch public IPs with no problems.

    I can't figure out what i'm doing wrong. I'm trying to avoid any sort of NAT for the voip so I'd like to use my public IPs. Does anyone know what I might be doing wrong?