static NAT "hangs"

[tato386]

I am running a 1921 with 15.0(1)M4  on it.  The router has a /29 public block assigned to it so I have a public IP for my router's GW, a public IP for the WAN interface on the router, a public IP for PAT and the three remaining public IPs I use them as static NATs for internal hosts.

My problem is that the particular static NAT assigned to static host1 seems to "hang" every few days.  You can ping the public IP and it will respond but the rest of the services of the host like www, ftp and telnet do not respond.  If I reboot the router then all services of host1 will work again.  Note that all other static IPs including the ones used for static host2, host3 and PAT will always work and never give any problems.

I am fairly certain that this is not a config problem so I have shuffled around the public-to-private NAT entries.  Basically whatever public IP I assign to this host1 will at some point hang.  The host2, host3 and PAT always work and never hang no matter what public IP I issue to them.

So since it isn't a problem with the public IP I changed the private IP of host1 and still it hung!!  This host1 happens to be a linux box.  host2 and host3 are a Windows server and a different flavor linux if that make some kind of difference.  I am out of ideas.

What can I do here?

Thanks,

Diego

[Danilo Dy]

Hi,

Check if the router is receiving a lot of connection from internal.external hosts and/or broadcast from internal hosts.

If you have purchase maintenance, I suggest you upgrade the IOS. I have that same IOS in my router and keeps crashing/restarting.

Best wishes,

Dandy

[Latchum Naidu]

Hi Diego,

I dont think router reboot all times is good a idea.
Did you try to clear the nat table by using command "clear ip nat tra fo" and see?

And also you can tell router to clear the NAT table automatically by seting up each tcp and udp nat timeouts to a reasonable amount, (tcp time-out after 24hrs default)

#ip nat translation udp-timeout 600
#ip tcp translation udp-timeout 600

Please rate the all helpfull posts.
Regards,
Naidu.

[tato386]

Latchum,

Those options look interesing.  I threw them in.  Now we need to wait and see what happens.

Thanks,

Diego

[tato386]

Thanks Dandy, our router is kinda old so it might not be on maintenance but I will check.

Rgds,

Diego