Hello,
On Fri, 2 Dec 2016, Mischa Verheul wrote:
> Hello,
>
> I'm trying to set up an IPVS NAT loadbalance solution with failover through
> keepalived and sync through "ipvsadm --start-daemon" on CentOS 7.
> Protocols such as HTTP work as expected, but FTP in passive mode isn't
> working for the FTP-data connection. It stops after issueing a list or get
> command.
>
> After I couldn't find out what was possibly wrong with my configuration
> after following documentation, I set up two basic IPVS setups for
> trial&error:
> Client -> IPVSmachine -> FTPserver
> 192.168.2.6 2.100/157.254 192.168.157.10/GW
> 192.168.157.254
>
> CentOS 5: uname -r 2.6.18-398.el5
> CentOS 7: uname -r 3.10.0-327.36.3.el7.x86_64
>
> Configuration on both IPVS machines is identical:
> ipvsadm -A -t 192.168.2.100:21 -s rr
> ipvsadm -a -t 192.168.2.100:21 -r 192.168.157.10:21 -m
> net.ipv4.ip_forward=1
> modprobe ip_vs_ftp
> no iptables rules
>
> [root@cent5 ~]# lsmod | grep -i ftp
> Module Size Used by
> ip_vs_ftp 39109 1
> ip_vs 122241 5 ip_vs_ftp,ip_vs_rr
>
>
> [root@cent7 ~]# lsmod | grep -i ftp
> Module Size Used by
> ip_vs_ftp 13079 0
> nf_nat 26146 1 ip_vs_ftp
> ip_vs 140944 5 ip_vs_rr,ip_vs_ftp
For the new kernels more modules are needed:
# 2.6.22+
modprobe nf_conntrack_ftp
modprobe nf_nat_ftp
# For ip_vs_ftp (NAT mode) to properly adjust TCP SEQ numbers:
echo 1 > /proc/sys/net/ipv4/netfilter/ip_conntrack_tcp_be_liberal
# or
echo 1 > /proc/sys/net/netfilter/nf_conntrack_tcp_be_liberal
# 2.6.36+, ip_vs_ftp (NAT mode) to properly adjust TCP SEQ numbers:
modprobe iptables_nat
You can find more info (a bit outdated, up to 2.6.36) in
HOWTO.txt here:
http://ja.ssi.bg/nfct/
i.e. you can check the example with iptables rules
in case you have some filtering applied.
Regards
--
Julian Anastasov <j...@ssi.bg>
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