Yep, there is a bug in older versions of IOS that supported 
dot1q trunks.  If you're running an older version, you can't 
have the native VLAN on a subinterface.  Place the 
configuration for the native (untagged) VLAN on the major 
interface and only use subinterfaces for the other tagged VLANs.

Regards,
John


http://home.attbi.com/~neiby


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---- On Tue, 19 Feb 2002, Gandolf ([EMAIL PROTECTED]) wrote:

> A problem I have come across on the 3500XL switches and dot1q 
trunking
> is
> when the XL switch expected the packets on the native VLAN to 
be
> untagged
> and the device on the other end of the trunk expects the 
packets to be
> tagged.  This prevents communication through the trunk on the 
native
> VLAN.
> The way to get around this is to set the native VLAN to a 
VLAN that does
> not
> exist anywhere on your network such as VLAN 999.  This way 
all packets
> going
> through the trunk are tagged and you will be able to route on 
vlan 24
> again.
> 
> 
> ""Sean Knox""  wrote in message
> [EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> > Hi all, I'm having a problem with intervlan routing on a 
3500XL. Port
> > FastEthernet0/17 is an access link and the host, part of 
VLAN23, is
> working
> > fine and can traverse the network. FastEthernet 0/18 is a 
802.1q trunk
> link
> > connected to a 802.1q aware host (a special network device 
my company
> > makes). Vlan24 is defined as the native vlan for this link 
on both
> sides
> > (the switch and 802.1q host). Connected to the 3500XL's 
FastEthernet
> 0/1
> is
> > a router with subifs defined with IP addresses and 
appropriate 802.1q
> VLAN
> > tags for each vlan. VLAN23, our access link, is routed fine 
throughout
> the
> > network. However, I can't ping the 802.1q host on VLAN24 
from the
> connected
> > router or elsewhere. The 802.1q device has its default 
gateway set to
> the
> > corresponding router subinterface. What am I missing? Below 
are the
> relevant
> > parts of the 3500XL config and router config.
> >
> > Thanks in advance!
> > Sean
> >
> >
> >
> > Relevant parts of show running-config on 3500XL:
> >
> > interface FastEthernet0/1
> >  duplex full
> >  speed 100
> >  switchport trunk encapsulation dot1q
> >  switchport mode trunk
> >
> > interface FastEthernet0/17
> >  duplex full
> >  speed 100
> >  switchport access vlan 23
> >  spanning-tree portfast
> >
> > interface FastEthernet0/18
> >  duplex half
> >  speed 100
> >  switchport trunk encapsulation dot1q
> >  switchport trunk native vlan 24
> >  switchport mode trunk
> >  spanning-tree portfast
> >
> > interface VLAN1
> >  ip address 10.6.200.2 255.255.255.0
> >  no ip directed-broadcast
> >  no ip route-cache
> > !
> > ip default-gateway 10.6.200.1
> >
> > Switch#show vlan
> > VLAN Name                             Status    Ports
> > ---- -------------------------------- ---------
> > -------------------------------
> > 1    default                          active    Fa0/2, 
Fa0/3, Fa0/4,
> Fa0/5,
> >                                                 Fa0/6, 
Fa0/7, Fa0/8,
> Fa0/9,
> >                                                 Fa0/10, 
Fa0/11,
> Fa0/12,
> > Fa0/13,
> >                                                 Fa0/14, 
Fa0/15,
> Fa0/16,
> > Fa0/19,
> >                                                 Fa0/20, 
Fa0/21,
> Fa0/22,
> > Fa0/23,
> >                                                 Fa0/24, 
Fa0/25,
> Fa0/26,
> > Fa0/27,
> >                                                 Fa0/28, 
Fa0/29,
> Fa0/30,
> > Fa0/31,
> >                                                 Fa0/32, 
Fa0/33,
> Fa0/34,
> > Fa0/35,
> >                                                 Fa0/36, 
Fa0/37,
> Fa0/38,
> > Fa0/39,
> >                                                 Fa0/40, 
Fa0/41,
> Fa0/42,
> > Fa0/43,
> >                                                 Fa0/44, 
Fa0/45,
> Fa0/46,
> > Fa0/47,
> >                                                 Fa0/48, 
Gi0/1, Gi0/2
> > 24   VLAN0024                         active
> >
> > VLAN Type  SAID       MTU   Parent RingNo BridgeNo Stp  
BrdgMode
> Trans1
> > Trans2
> > ---- ----- ---------- ----- ------ ------ -------- ---- ----
----
> ------
> > ------
> > 1    enet  100001     1500  -      -      -        -    -
        1002
> 1003
> > 24   enet  100024     1500  -      -      -        -    -
        0    
>  0
> >
> > Router8510#show run
> >
> > interface FastEthernet1/0/4
> >  description Core8500 to 3500XL
> >  ip address 10.6.200.2 255.255.255.0
> >  duplex full
> >  speed 100
> >
> > interface FastEthernet1/0/4.23
> >  encapsulation dot1Q 23
> >  ip address 10.6.23.1 255.255.255.0
> >
> > interface FastEthernet1/0/4.24
> >  encapsulation dot1Q 24
> >  ip address 10.6.24.1 255.255.255.0
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