question about gre tunneling in centos 6.3
 

hi ,
i wan tto ask about tunneling in centos .
my 1st question is , i want to know if my kernel is supportting tunneling gre or not
noe that when i type the command
[root@squid ~]# insmod ip_gre
insmod: can't read 'ip_gre': No such file or directory
==========================================================================
as u see i have error above , my question is , does that mean that gre is not supported on my kernel ?
here is outout of lsmod :
[root@squid ~]# lsmod
Module Size Used by
ip_gre 18485 0
gre 2102 1 ip_gre
autofs4 32719 3
sunrpc 228199 1
xt_tcpudp 3557 1
xt_mark 1284 1
xt_TPROXY 8418 1
nf_tproxy_core 1299 1 xt_TPROXY,[permanent]
xt_socket 5944 1
nf_defrag_ipv4 1546 2 xt_TPROXY,xt_socket
ip6_tables 20264 2 xt_TPROXY,xt_socket
nf_defrag_ipv6 10537 2 xt_TPROXY,xt_socket
ipv6 336052 44790 ip_gre,xt_TPROXY,xt_socket,nf_defrag_ipv6
iptable_mangle 1736 1
ip_tables 19992 1 iptable_mangle
x_tables 24637 7 xt_tcpudp,xt_mark,xt_TPROXY,xt_socket,ip6_tables,iptable_mangle,ip_tables
iTCO_wdt 5874 0
iTCO_vendor_support 2991 1 iTCO_wdt
dcdbas 8290 0
acpi_pad 88129 0
coretemp 7044 0
kvm_intel 129046 0
kvm 426331 1 kvm_intel
crc32c_intel 2155 0
ghash_clmulni_intel 4604 0
microcode 113081 0
pcspkr 2015 0
sb_edac 13624 0
edac_core 53713 1 sb_edac
lpc_ich 11881 0
mfd_core 3916 1 lpc_ich
shpchp 27862 0
sg 30745 0
tg3 153073 0
ext4 493299 5
mbcache 7312 1 ext4
jbd2 89008 1 ext4
sr_mod 15821 0
cdrom 40869 1 sr_mod
sd_mod 40360 6
crc_t10dif 1508 1 sd_mod
aesni_intel 45641 0
ablk_helper 2958 1 aesni_intel
cryptd 10421 3 ghash_clmulni_intel,aesni_intel,ablk_helper
lrw 4183 1 aesni_intel
aes_x86_64 7928 1 aesni_intel
xts 3427 1 aesni_intel
gf128mul 7960 2 lrw,xts
ahci 22608 0
libahci 25519 1 ahci
megaraid_sas 79406 5
wmi 10430 0
dm_mirror 14325 0
dm_region_hash 10927 1 dm_mirror
dm_log 9546 2 dm_mirror,dm_region_hash
dm_mod 82235 2 dm_mirror,dm_log
=================================
3rd question im trying to do the tunnel configs and it seems to be accepted from terminal
i mean if i type the commands below , no error are shown
iptunnel add gre1 mode gre remote 10.80.3.2 local 10.80.2.2 dev eth0
ifconfig gre1 10.0.0.1 up
========================================

my main question is ,

based on the outputs above
dos my system acccept , support the tunnel gre ???

with my best regards

Follow this guide. http://ernest.utreg.net/?page=gre_tunneling_cookbook

As you can see the modprobe shows it is available. There are other guides also. One page complains why redhat doesn't offer details but I am sure I have seen redhat doc's on this.