by I’m using a Cisco VA887 as a modem, and here is the config, which should work with most UK ISPs.
I also used the 887 as a PPPoE router previously and here is my config for that.
My unit has had the fan removed, hence the ‘nolog’ option for the fan.
To enhance passive cooling, I removed two plastic parts (one of which held the fan) on the fan side, and on the other side I removed the two metal ‘sides’, which were blocking any cross ventilation. The unit runs a lot cooler now without the fan.
You will also note that the MTU has been set to 1508 for *both* the ‘Ethernet0’ and ‘Vlan1’ interfaces. This enables my PPP config to use an MTU of 1500 and prevent fragmentation.
sh run Building configuration... Current configuration : 1611 bytes ! ! Last configuration change at 16:21:19 UTC Fri Apr 28 2023 version 15.3 no service pad service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname Router ! boot-start-marker boot system flash c880data-universalk9-mz.153-3.M.bin boot-end-marker ! ! logging discriminator nolog msg-body drops Fan logging buffered discriminator nolog logging console discriminator nolog enable secret 5enable password ! no aaa new-model memory-size iomem 10 ! ! no ip routing ! ! ! ! ! ! no ip cef no ipv6 cef ! ! license udi pid CISCO887VA-K9 sn FCZ153394TL license boot module c880-data level advsecurity ! ! ! ! ! ! ! controller VDSL 0 operating mode vdsl2 firmware filename flash:VA_A_39d_B_38h3_24h_1.bin ! ! ! ! ! ! ! ! ! ! interface Ethernet0 mtu 1508 no ip address no ip route-cache ! interface Ethernet0.101 encapsulation dot1Q 101 no ip route-cache bridge-group 1 ! interface ATM0 no ip address no ip route-cache shutdown no atm ilmi-keepalive ! interface FastEthernet0 no ip address ! interface FastEthernet1 no ip address shutdown ! interface FastEthernet2 no ip address shutdown ! interface FastEthernet3 no ip address shutdown ! interface Vlan1 mtu 1508 no ip address ip virtual-reassembly in no ip route-cache bridge-group 1 ! ip forward-protocol nd no ip http server no ip http secure-server ! ! ! bridge 1 protocol ieee ! banner motd ^CSet terminal length 0 to view full config^C ! line con 0 no modem enable line aux 0 line vty 0 4 password login transport input all ! ! end