Cannot change MTU for ADSL interface

[f2b]

Hi

I cannot change the MTU on the ADSL interface. The fe0 is 1500 and the Firewall WAN port is set to 1404 (recommended by Sonicwall, but the ADSL int is at the default mtu of 4470. Tried everything to change this but still shows the same. Not sure also to change thre FEO to 1404.
Trying to find the best setting as we're based in southern Spain so not sure correct MTU.

Not sure if I should be changing this. Can enybody advise please? Details below.

Thanks


Cisco IOS Software, 2800 Software (C2800NM-ADVSECURITYK9-M), Version 12.3(8)T8,
RELEASE SOFTWARE (fc1)
Technical Support:

http://www.cisco.com/techsupport

Copyright (c) 1986-2005 by Cisco Systems, Inc.
Compiled Wed 06-Apr-05 16:46 by yiyan

ROM: System Bootstrap, Version 12.3(8r)T7, RELEASE SOFTWARE (fc1)
ROM: Cisco IOS Software, 2800 Software (C2800NM-SPSERVICESK9-M), Version 12.3(8)
T8, RELEASE SOFTWARE (fc1)



FastEthernet0/0 is up, line protocol is up
Hardware is MV96340 Ethernet, address is 0013.c4e5.dcb0 (bia 0013.c4e5.dcb0)
Internet address is 192.168.47.1/24
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
reliability 255/255, txload 4/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 100Mb/s, 100BaseTX/FX




ATM0/0/0 is up, line protocol is up
Hardware is DSLSAR (with Alcatel ADSL Module)
MTU 4470 bytes, sub MTU 4470, BW 640 Kbit, DLY 800 usec,
reliability 255/255, txload 41/255, rxload 194/255
Encapsulation ATM, loopback not set
Encapsulation(s): AAL5 AAL2, PVC mode
23 maximum active VCs, 256 VCs per VP, 1 current VCCs
VC Auto Creation Disabled.
VC idle disconnect time: 300 seconds
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 902

 

[JOAMON]

Not sure if you should be changing it either but are you shutting down the interface and then bring it back up after a setting change. Some settings will load on startup and typically will not change unless you bounce the interface down and up.

 

[f2b]

Hi Joamon

"Not sure if you should be changing it either"
You think I should not be changing this?

 

[NettableWalker]

ADSL is supposed to work as PPP over Ethernet or PPP over ATM, in which case it is the IP protocol which runs on an ATM infrastructure. You shouldn't need to change the ATM details.

I would try to change the MTU on the Dialer interface rather than the ATM interface.

MCP,CCA,CCNA, Net+, Half CCNP...

 

[f2b]

Hi

Thanks for that. I don't actually have a dialer interface.

interface ATM0/0/0
no ip address
no atm ilmi-keepalive
dsl operating-mode auto
!
interface ATM0/0/0.1 point-to-point
ip address xx.xx.xx.xx 255.255.255.0
no ip redirects
no ip unreachables
ip nat outside
ip virtual-reassembly
pvc 8/32
!

 

[NettableWalker]

Does that work?

MCP,CCA,CCNA, Net+, Half CCNP...

 

[f2b]

Hi
I don't have a dialer interface so where do I test the MTU?

Thanks