Frag reassembly time exceeded

Alt Linux Master 2.2 (2.4.25)
Маршрутизатор P4/512Mb, 3 интерфейса
Сеть большая - несколько сот машин
[root@qwe bind]# ping -s 64000 192.168.1.20
PING 192.168.1.20 (192.168.1.20) 64000(64028) bytes of data.
64008 bytes from 192.168.1.20: icmp_seq=19 ttl=128 time=19.7 ms
64008 bytes from 192.168.1.20: icmp_seq=20 ttl=128 time=20.0 ms
64008 bytes from 192.168.1.20: icmp_seq=21 ttl=128 time=21.6 ms
64008 bytes from 192.168.1.20: icmp_seq=25 ttl=128 time=18.9 ms
64008 bytes from 192.168.1.20: icmp_seq=28 ttl=128 time=20.5 ms
64008 bytes from 192.168.1.20: icmp_seq=32 ttl=128 time=17.8 ms
64008 bytes from 192.168.1.20: icmp_seq=34 ttl=128 time=19.8 ms
64008 bytes from 192.168.1.20: icmp_seq=35 ttl=128 time=22.3 ms
64008 bytes from 192.168.1.20: icmp_seq=40 ttl=128 time=20.0 ms
64008 bytes from 192.168.1.20: icmp_seq=43 ttl=128 time=17.9 ms
64008 bytes from 192.168.1.20: icmp_seq=48 ttl=128 time=17.8 ms
64008 bytes from 192.168.1.20: icmp_seq=50 ttl=128 time=19.8 ms
64008 bytes from 192.168.1.20: icmp_seq=60 ttl=128 time=20.4 ms
From 192.168.1.20 icmp_seq=1 Frag reassembly time exceeded
From 192.168.1.20 icmp_seq=2 Frag reassembly time exceeded
From 192.168.1.20 icmp_seq=3 Frag reassembly time exceeded
From 192.168.1.20 icmp_seq=4 Frag reassembly time exceeded
From 192.168.1.20 icmp_seq=5 Frag reassembly time exceeded
From 192.168.1.20 icmp_seq=6 Frag reassembly time exceeded
From 192.168.1.20 icmp_seq=7 Frag reassembly time exceeded
64008 bytes from 192.168.1.20: icmp_seq=72 ttl=128 time=18.4 ms
From 192.168.1.20 icmp_seq=8 Frag reassembly time exceeded
From 192.168.1.20 icmp_seq=9 Frag reassembly time exceeded
From 192.168.1.20 icmp_seq=10 Frag reassembly time exceeded
From 192.168.1.20 icmp_seq=11 Frag reassembly time exceeded
From 192.168.1.20 icmp_seq=12 Frag reassembly time exceeded
64008 bytes from 192.168.1.20: icmp_seq=77 ttl=128 time=20.0 ms
From 192.168.1.20 icmp_seq=13 Frag reassembly time exceeded

В чем может быть причина? Может в /proc что-то можно подкрутить?