Cisco 867VAE drops connection on DHCP lease timeout

[itservicesyd]

Hey!

We have a very annoying problem on our hands. I'm no IOS expert, but I make do.

We've got a Telia DSL connection that has a 20 minute DHCP lease timer. Every 20 minutes when it shakes hand again, the connection drops for about 5 seconds. This because the Cisco thinks that administratively shutting down the interface is a good idea....

How do I stop this behavior? I've tried manually setting

<ip dhcp client lease 1 0 0>

(for 1 day lease) but it completely disregards that.

Best would obviously be to stop it shutting down the interface every time, but worst case scenario I'll take a solution with a longer DHCP lease since the address rarely changes.

<snip from log>

*Aug  1 01:44:43.514 PCTime: %DHCP-6-ADDRESS_ASSIGN: Interface ATM0.1 assigned DHCP address 81.230.xxx.xx, mask 255.255.255.0, hostname elsa




*Aug  1 02:04:48.498 PCTime: %DHCP-5-RESTART: Interface ATM0.1 is being restarted by DHCP




*Aug  1 02:04:56.106 PCTime: %DHCP-6-ADDRESS_ASSIGN: Interface ATM0.1 assigned DHCP address 81.230.xxx.xx, mask 255.255.255.0, hostname elsa




*Aug  1 02:25:01.050 PCTime: %DHCP-5-RESTART: Interface ATM0.1 is being restarted by DHCP

</snip>

It's running firmware

c860vae-ipbasek9-mz.153-2

I'm attaching the current running-config as well.

Thank you in advance!

Best Regards

Daniel

[marioderosa2008]

Hi there, yes i forgot to update that I had the same issue. i had a static NAT port forwarding everything, including the DHCP responses from the ISP.

However, what I could not get to work was to have a static NAT portforwarding everything, together with a static NAT only portforwarding the DHCP responses... The NAT forwarding everything always took precidence.

If you manage to get this working, please let me know.

thanks

Mario

[slavochka]

Could you post your config

[itservicesyd]

Could I quickly hijack my own thread to ask how to properly port forward a range of ports? We need loads of SIP ports (both TCP and UDP, like 9000-9999 to IP 192.168.200.100 for example) forwarded to the server, and my knowledge of IOS is still limited. That's why I made static NAT to begin with...

Only if you have time on the fly as this should really be a separate thread if anything :) Cheers

PS. I've searched for it, but there are so many different answers I get confused.

[slavochka]

I never tried it:
https://supportforums.cisco.com/discussion/11593786/nat-udp-port-range-forwarding-howto
but as you could see may be some problems with udp.
Easiest way insert only 2 lines in config:

ip nat inside source static 192.168.200.100 interface ATM0.1
ip nat inside source static udp 192.168.200.1 68 interface ATM0.1 68

In case of Asterisk PBX better to choose IAX protocol it use only one port also it has better performance.

[paul driver]

Have you got this working?

[paul driver]

Hello

So you are still having problems with Dropping connection?

res

Paul

[itservicesyd]

Hello Paul,

I don't know yet. I haven't had the chance to try it out yet, sadly. It's been hectic lately and internal problems like these have to fall behind.
I will for sure try this out next week however, and I'll update with correct answer etc accordingly.

Regards
Daniel

[itservicesyd]

Hello everyone!

I'll just take this moment to thank slavochka (and the rest of you for helping) for the solution. We're running without any hickups now, as soon as I entered:

ip nat inside source static udp 192.168.200.1 68 interface ATM0.1 68

I noticed that the correct answer is already marked, but consider this thread fully closed now
Still funny that the Cisco support didn't manage to find this, but I know they're humans too.

Cheers!
 

Regards
Daniel