What on earth am I doing wrong? [root@osprey ~]# ifconfig eth0 mtu 1492 SIOCSIFMTU: Invalid argument [root@osprey ~]# ifconfig eth0 inet mtu 1492 SIOCSIFMTU: Invalid argument I tried stopping eth0 (ifconfig eth0 down), then executing the mtu size change, but it didn't help. I also tried adding MTU=1492 in /etc/sysconfig/network-scripts/ifcfg-eth0, but on network restart I get the same SIOCSIFMTU error. Background info: Abit AV8 motherboard with Via Velocity 6122 Gbit onboard nic. Autonegotiation is on. >From dmesg: VIA Networking Velocity Family Gigabit Ethernet Adapter Driver Ver. 1.13 Copyright (c) 2002, 2003 VIA Networking Technologies, Inc. Copyright (c) 2004 Red Hat Inc. GSI 17 sharing vector 0xB1 and IRQ 17 ACPI: PCI Interrupt 0000:00:0e.0[A] -> GSI 22 (level, low) -> IRQ 17 PCI: Via IRQ fixup for 0000:00:0e.0, from 10 to 1 eth0: VIA Networking Velocity Family Gigabit Ethernet Adapter eth0: Ethernet Address: 00:50:8D:EF:90:69 [root@osprey ~]# uname -a;ifconfig eth0 Linux osprey 2.6.16-1.2111_FC5 #1 SMP Thu May 4 21:16:04 EDT 2006 x86_64 x86_64 x86_64 GNU/Linux eth0 Link encap:Ethernet HWaddr 00:50:8D:EF:90:69 inet addr:192.168.1.3 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::250:8dff:feef:9069/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:6274 errors:0 dropped:0 overruns:0 frame:0 TX packets:6011 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:4922524 (4.6 MiB) TX bytes:1218897 (1.1 MiB) Interrupt:17 Base address:0xd000