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Cisco NAT -> non-standard FTP port..

I have a set of users dialing into a modem pool that via NAT appears as a single valid address. These users are attempting to access an FTP server running on a non-standard port (6222) elsewhere on the internet and looking at the traffic it appears that their "PORT" command are not being translated by the Cisco to reflect the correct external address. I have attempted to use the "ip nat service" command to support both port 21 and 62222 but it does not appear to make a difference. I have tried assigning the service both to a list defining the single external address and the NAT address pool. Any


Config file (some parts removed for security):


version 12.0

service timestamps debug uptime

service timestamps log uptime

no service password-encryption



ip subnet-zero

ip name-server a.b.c.d

ip name-server e.f.g.h




interface Ethernet0/0

ip address i.j.k.l

no ip directed-broadcast

ip nat outside

no ip mroute-cache

no cdp enable


interface Group-Async1

ip unnumbered Ethernet0/0

no ip directed-broadcast

ip nat inside

encapsulation ppp

ip tcp header-compression passive

async mode dedicated

peer default ip address pool setup_pool

ppp authentication chap pap

group-range 33 40


ip local pool setup_pool

ip nat service list 1 ftp tcp port 21

ip nat service list 1 ftp tcp port 6222

ip nat inside source list 1 interface Ethernet0/0 overload

ip classless

ip route g.h.i.j


access-list 1 permit

dialer-list 1 protocol ip permit

dialer-list 1 protocol ipx permit

snmp-server community public RO


line con 0

exec-timeout 0 0

transport input none

line 33 40

session-timeout 5 output

autoselect ppp

modem InOut

flowcontrol hardware

line aux 0

line vty 0 4

password xxxx



New Member

Re: Cisco NAT -> non-standard FTP port..

Just to clarify, this is on a Cisco 2610 running Version 12.0(10).

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