|
In doing a quick with the 2.4.28 kernel,
after flushing the cache with ip route flush cache, 5mins later we get the
infamous “dst cache overflow” messages. Doing a route –Cn |
wc results in the following on each time the messages started to appear: 5mins 4095 29609 315201 5mins 4093 29575 315043 Our /proc/sys/net/ipv4/route/max_size
is set to 4096, so I guess that’s why we get the messages, but eventually
the network connections stop and the firewall needs to be hard rebooted. So I’m
not sure of the point in setting that, unless there is a memory leak somewhere…
Thanks, Michael Brown From:
fedora-list-bounces@xxxxxxxxxx [mailto:fedora-list-bounces@xxxxxxxxxx] On Behalf Of Fedora I have been searching all over the internet for a solution
to the common “kernel: dst cache overflow” problem people have been
having… Here’s my synopsis, I am running 14 Linux firewalls, 9 on
Fedora core 2, 1 on Fedora core 1 and 3 on Red Hat 9. All of the firewalls have
about 3-4 Copper Gig NICs, on Dell PowerEdge 700 with 512mb memory and a P4
2.8Ghz CPU. The firewalls have just above bare minimal pkgs installs, all
installed from a kickstart file and all services (if any un-used) have been
turn off and disable in the runlevels. These are only firewalls for internet
and private traffic across T1’s and higher. All fedora core 2
firewalls have and running the latest kernel 2.6.9-1.6_FC2smp, but each kernel
before that also had the errors, so there are no fixes in the kernel. All Red
Hat firewalls are running 2.4.25 kernel and the 1 fedora core 1 is running
2.4.26, but none of them are experiencing this issue. On the Fedora Core 2 firewalls, I get the below kernel
messages after a certain amount of traffic, what that amount is, I do not know.
kernel: dst cache overflow kernel: printk: 52 messages suppressed. kernel: dst cache overflow kernel: printk: 36 messages suppressed. kernel: dst cache overflow After so much traffic or time, the
firewall becomes unresponsive on the network and I may or may not get this new
message, and the system needs a hard reboot. syslogd: sendto: No buffer space available kernel: dst cache overflow last message repeated 5 times last message repeated 9 times last message repeated 3 times syslogd: sendto: No buffer space available kernel: dst cache overflow last message repeated 3 times last message repeated 3 times I have tried just resetting the network ( service network
restart), I also tried just to stop the network for a few hours, I tried the
recommendation of setting the route max_size in
/proc/sys/net/ipv4/route/max_size (http://seclists.org/lists/vulnwatch/2003/Apr-Jun/0076.html),
none seemed to help. I am now trying a custom 2.4.28 kernel on one of the
firewalls to see if that may help. Has anyone run into this and fixed it? It seems to be only
with Fedora Core 2, I am curious if Fedora 3 would make a difference, but I am
not ready to leap into that bird nest just yet. Thanks, Michael Brown |
