[strongSwan] Roadwarriors can't ping eachother

Noel Kuntze noel.kuntze+strongswan-users-ml at thermi.consulting
Sat Sep 9 15:57:32 CEST 2017


Hi Bas,

Please provide the outputs of `iptables-save -c` on all hosts
and the output of `sysctl -A | grep rp_filter`. `iptables -S` is not useful.

Kind regards

Noel

On 09.09.2017 15:50, Bas van Dijk wrote:
> Hi Noel,
> 
> These are the firewall rules of all hosts after establishing the tunnels (all the NFLOG rules will be removed eventually, they're currently used for debugging):
> 
> [alice] $ iptables -S 
> -P INPUT ACCEPT
> -P FORWARD ACCEPT
> -P OUTPUT ACCEPT
> -N nixos-fw
> -N nixos-fw-accept
> -N nixos-fw-log-refuse
> -N nixos-fw-refuse
> -A INPUT -s 10.0.0.0/24 <http://10.0.0.0/24> -d 10.0.0.1/32 <http://10.0.0.1/32> -i eth1 -m policy --dir in --pol ipsec --reqid 1 --proto esp -j ACCEPT
> -A INPUT -m addrtype ! --dst-type LOCAL -m policy --dir in --pol ipsec -j NFLOG --nflog-group 5
> -A INPUT -m addrtype --dst-type LOCAL -m policy --dir in --pol ipsec -j NFLOG --nflog-group 5
> -A INPUT -p udp -m multiport --dports 500,4500 -j NFLOG --nflog-group 5
> -A INPUT -p ah -j NFLOG --nflog-group 5
> -A INPUT -p esp -j NFLOG --nflog-group 5
> -A INPUT -j nixos-fw
> -A FORWARD -s 10.0.0.0/24 <http://10.0.0.0/24> -d 10.0.0.1/32 <http://10.0.0.1/32> -i eth1 -m policy --dir in --pol ipsec --reqid 1 --proto esp -j ACCEPT
> -A FORWARD -s 10.0.0.1/32 <http://10.0.0.1/32> -d 10.0.0.0/24 <http://10.0.0.0/24> -o eth1 -m policy --dir out --pol ipsec --reqid 1 --proto esp -j ACCEPT
> -A OUTPUT -s 10.0.0.1/32 <http://10.0.0.1/32> -d 10.0.0.0/24 <http://10.0.0.0/24> -o eth1 -m policy --dir out --pol ipsec --reqid 1 --proto esp -j ACCEPT
> -A OUTPUT -m policy --dir out --pol ipsec -j NFLOG --nflog-group 5
> -A OUTPUT -p udp -m multiport --dports 500,4500 -j NFLOG --nflog-group 5
> -A OUTPUT -p ah -j NFLOG --nflog-group 5
> -A OUTPUT -p esp -j NFLOG --nflog-group 5
> -A nixos-fw -i lo -j nixos-fw-accept
> -A nixos-fw -m conntrack --ctstate RELATED,ESTABLISHED -j nixos-fw-accept
> -A nixos-fw -p icmp -m icmp --icmp-type 8 -j nixos-fw-accept
> -A nixos-fw -j nixos-fw-log-refuse
> -A nixos-fw-accept -j ACCEPT
> -A nixos-fw-log-refuse -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -j LOG --log-prefix "rejected connection: " --log-level 6
> -A nixos-fw-log-refuse -m pkttype ! --pkt-type unicast -j nixos-fw-refuse
> -A nixos-fw-log-refuse -j nixos-fw-refuse
> -A nixos-fw-refuse -j DROP
> 
> [carol] $ iptables -S 
> -P INPUT ACCEPT
> -P FORWARD ACCEPT
> -P OUTPUT ACCEPT
> -N nixos-fw
> -N nixos-fw-accept
> -N nixos-fw-log-refuse
> -N nixos-fw-refuse
> -A INPUT -s 10.0.0.0/24 <http://10.0.0.0/24> -d 10.0.0.2/32 <http://10.0.0.2/32> -i eth1 -m policy --dir in --pol ipsec --reqid 1 --proto esp -j ACCEPT
> -A INPUT -m addrtype ! --dst-type LOCAL -m policy --dir in --pol ipsec -j NFLOG --nflog-group 5
> -A INPUT -m addrtype --dst-type LOCAL -m policy --dir in --pol ipsec -j NFLOG --nflog-group 5
> -A INPUT -p udp -m multiport --dports 500,4500 -j NFLOG --nflog-group 5
> -A INPUT -p ah -j NFLOG --nflog-group 5
> -A INPUT -p esp -j NFLOG --nflog-group 5
> -A INPUT -j nixos-fw
> -A FORWARD -s 10.0.0.0/24 <http://10.0.0.0/24> -d 10.0.0.2/32 <http://10.0.0.2/32> -i eth1 -m policy --dir in --pol ipsec --reqid 1 --proto esp -j ACCEPT
> -A FORWARD -s 10.0.0.2/32 <http://10.0.0.2/32> -d 10.0.0.0/24 <http://10.0.0.0/24> -o eth1 -m policy --dir out --pol ipsec --reqid 1 --proto esp -j ACCEPT
> -A OUTPUT -s 10.0.0.2/32 <http://10.0.0.2/32> -d 10.0.0.0/24 <http://10.0.0.0/24> -o eth1 -m policy --dir out --pol ipsec --reqid 1 --proto esp -j ACCEPT
> -A OUTPUT -m policy --dir out --pol ipsec -j NFLOG --nflog-group 5
> -A OUTPUT -p udp -m multiport --dports 500,4500 -j NFLOG --nflog-group 5
> -A OUTPUT -p ah -j NFLOG --nflog-group 5
> -A OUTPUT -p esp -j NFLOG --nflog-group 5
> -A nixos-fw -i lo -j nixos-fw-accept
> -A nixos-fw -m conntrack --ctstate RELATED,ESTABLISHED -j nixos-fw-accept
> -A nixos-fw -p icmp -m icmp --icmp-type 8 -j nixos-fw-accept
> -A nixos-fw -j nixos-fw-log-refuse
> -A nixos-fw-accept -j ACCEPT
> -A nixos-fw-log-refuse -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -j LOG --log-prefix "rejected connection: " --log-level 6
> -A nixos-fw-log-refuse -m pkttype ! --pkt-type unicast -j nixos-fw-refuse
> -A nixos-fw-log-refuse -j nixos-fw-refuse
> -A nixos-fw-refuse -j DROP
> 
> [moon] $ iptables -S 
> -P INPUT ACCEPT
> -P FORWARD ACCEPT
> -P OUTPUT ACCEPT
> -N nixos-fw
> -N nixos-fw-accept
> -N nixos-fw-log-refuse
> -N nixos-fw-refuse
> -A INPUT -m addrtype ! --dst-type LOCAL -m policy --dir in --pol ipsec -j NFLOG --nflog-group 5
> -A INPUT -m addrtype --dst-type LOCAL -m policy --dir in --pol ipsec -j NFLOG --nflog-group 5
> -A INPUT -p udp -m multiport --dports 500,4500 -j NFLOG --nflog-group 5
> -A INPUT -p ah -j NFLOG --nflog-group 5
> -A INPUT -p esp -j NFLOG --nflog-group 5
> -A INPUT -j nixos-fw
> -A FORWARD -s 10.0.0.2/32 <http://10.0.0.2/32> -d 10.0.0.0/24 <http://10.0.0.0/24> -i eth1 -m policy --dir in --pol ipsec --reqid 2 --proto esp -j ACCEPT
> -A FORWARD -s 10.0.0.0/24 <http://10.0.0.0/24> -d 10.0.0.2/32 <http://10.0.0.2/32> -o eth1 -m policy --dir out --pol ipsec --reqid 2 --proto esp -j ACCEPT
> -A FORWARD -s 10.0.0.1/32 <http://10.0.0.1/32> -d 10.0.0.0/24 <http://10.0.0.0/24> -i eth1 -m policy --dir in --pol ipsec --reqid 1 --proto esp -j ACCEPT
> -A FORWARD -s 10.0.0.0/24 <http://10.0.0.0/24> -d 10.0.0.1/32 <http://10.0.0.1/32> -o eth1 -m policy --dir out --pol ipsec --reqid 1 --proto esp -j ACCEPT
> -A OUTPUT -m policy --dir out --pol ipsec -j NFLOG --nflog-group 5
> -A OUTPUT -p udp -m multiport --dports 500,4500 -j NFLOG --nflog-group 5
> -A OUTPUT -p ah -j NFLOG --nflog-group 5
> -A OUTPUT -p esp -j NFLOG --nflog-group 5
> -A nixos-fw -i lo -j nixos-fw-accept
> -A nixos-fw -m conntrack --ctstate RELATED,ESTABLISHED -j nixos-fw-accept
> -A nixos-fw -p udp -m udp --dport 4500 -j nixos-fw-accept
> -A nixos-fw -p udp -m udp --dport 500 -j nixos-fw-accept
> -A nixos-fw -p icmp -m icmp --icmp-type 8 -j nixos-fw-accept
> -A nixos-fw -j nixos-fw-log-refuse
> -A nixos-fw-accept -j ACCEPT
> -A nixos-fw-log-refuse -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -j LOG --log-prefix "rejected connection: " --log-level 6
> -A nixos-fw-log-refuse -m pkttype ! --pkt-type unicast -j nixos-fw-refuse
> -A nixos-fw-log-refuse -j nixos-fw-refuse
> -A nixos-fw-refuse -j DROP
> 
> 
> On 9 September 2017 at 15:34, Noel Kuntze <noel.kuntze+strongswan-users-ml at thermi.consulting <mailto:noel.kuntze+strongswan-users-ml at thermi.consulting>> wrote:
> 
>     Hi,
> 
>     Check your iptables rules.
> 
>     Kind regards
> 
>     Noel
> 
>     On 09.09.2017 14 <tel:09.09.2017%2014>:06, Bas van Dijk wrote:
>     > Dear list,
>     >
>     > (I accidentally sent a previous message <https://groups.google.com/forum/#%21topic/strongswan-users/2ytikPcg7jA <https://groups.google.com/forum/#%21topic/strongswan-users/2ytikPcg7jA>> to the read-only strongswan-users at googlegroups.com <mailto:strongswan-users at googlegroups.com> <mailto:strongswan-users at googlegroups.com <mailto:strongswan-users at googlegroups.com>>. So let's try the real list.)
>     >
>     > I'm working on another NixOS strongswan test. This time I have two roadwarriors alice and carol that set up a connection to gateway moon. They request a virtual IP. The gateway moon assigns virtual IP addresses from a pool per roadwarrior containing a single IP address. Authentication is based on X.509 certificates. In order to test the tunnel alice and carol ping each other. The test configuration can be found in:
>     >
>     > https://github.com/LumiGuide/nixpkgs/blob/strongswan-swanctl-pubkey-test/nixos/tests/strongswan-swanctl-pubkey.nix <https://github.com/LumiGuide/nixpkgs/blob/strongswan-swanctl-pubkey-test/nixos/tests/strongswan-swanctl-pubkey.nix>
>     >
>     > The roadwarriors alice and carol can successfully establish a CHILD_SA with the gateway moon. The problem is that the roadwarriors can't ping eachother. 
>     >
>     > This is a tcpdump on alice while initiating the CHILD_SA and trying to ping carol:
>     >
>     > [alice] $ tcpdump -s 0 -n -i nflog:5
>     > tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
>     > listening on nflog:5, link-type NFLOG (Linux netfilter log messages), capture size 262144 bytes
>     > # swanctl -i --child alice
>     > 11:05:07.318185 IP 192.168.1.1.500 > 192.168.1.3.500: isakmp: parent_sa ikev2_init[I]
>     > 11:05:07.318291 IP 192.168.1.3.500 > 192.168.1.1.500: isakmp: parent_sa ikev2_init[R]
>     > 11:05:07.318296 IP 192.168.1.1.4500 > 192.168.1.3.4500: NONESP-encap: isakmp: child_sa  ikev2_auth[I]
>     > 11:05:07.318308 IP 192.168.1.1.4500 > 192.168.1.3.4500: NONESP-encap: isakmp: child_sa  ikev2_auth[I]
>     > 11:05:08.346181 IP 192.168.1.3.4500 > 192.168.1.1.4500: NONESP-encap: isakmp: child_sa  ikev2_auth[R]
>     > 11:05:08.346196 IP 192.168.1.3.4500 > 192.168.1.1.4500: NONESP-encap: isakmp: child_sa  ikev2_auth[R]
>     > # ping -c 1 10.0.0.2
>     > 11:05:15.898172 IP 192.168.1.1 > 10.0.0.2 <http://10.0.0.2>: ICMP echo request, id 1120, seq 1, length 64
>     > 11:05:15.898200 IP 192.168.1.1 > 10.0.0.2 <http://10.0.0.2>: ICMP echo request, id 1120, seq 1, length 64
>     > 11:05:15.898205 IP 192.168.1.1 > 192.168.1.3 <http://192.168.1.3>: ESP(spi=0xc6877d56,seq=0x1), length 136
>     >
>     > So it looks like the ping packet gets encapsulated and send to moon. This is the dump on moon:
>     >
>     > [moon] $ tcpdump -s 0 -n -i nflog:5
>     > tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
>     > listening on nflog:5, link-type NFLOG (Linux netfilter log messages), capture size 262144 bytes
>     > 11:05:07.170190 IP 192.168.1.1.500 > 192.168.1.3.500: isakmp: parent_sa ikev2_init[I]
>     > 11:05:07.170218 IP 192.168.1.3.500 > 192.168.1.1.500: isakmp: parent_sa ikev2_init[R]
>     > 11:05:07.170221 IP 192.168.1.1.4500 > 192.168.1.3.4500: NONESP-encap: isakmp: child_sa  ikev2_auth[I]
>     > 11:05:07.170227 IP 192.168.1.1.4500 > 192.168.1.3.4500: NONESP-encap: isakmp: child_sa  ikev2_auth[I]
>     > 11:05:08.225827 IP 192.168.1.3.4500 > 192.168.1.1.4500: NONESP-encap: isakmp: child_sa  ikev2_auth[R]
>     > 11:05:08.225843 IP 192.168.1.3.4500 > 192.168.1.1.4500: NONESP-encap: isakmp: child_sa  ikev2_auth[R]
>     >
>     > 11:05:15.777787 IP 192.168.1.1 > 192.168.1.3 <http://192.168.1.3>: ESP(spi=0xc6877d56,seq=0x1), length 136
>     >
>     > So moon receives the encapsulated ping message from alice but it never reroutes it to carol. Is this caused by a bad routing configuration? These are the routes on alice and her auto-generated swanctl configuration:
>     >
>     > [alice] $ ip route list table 220
>     > 10.0.0.0/24 <http://10.0.0.0/24> <http://10.0.0.0/24> via 192.168.1.3 dev eth1 proto static src 192.168.1.1 
>     >
>     > [alice] $ cat /etc/swanctl/swanctl.conf
>     > connections {
>     >   alice {
>     >     children {
>     >       alice {
>     >         remote_ts = 10.0.0.0/24 <http://10.0.0.0/24> <http://10.0.0.0/24>
>     >         start_action = trap
>     >         updown = /nix/store/jdcviy5z25xamq35g8k9qbdpskkx3w9g-strongswan-5.6.0/libexec/ipsec/_updown iptables
>     >       }
>     >     }
>     >     local-main {
>     >       auth = pubkey
>     >       certs = aliceCert.der
>     >       id = alice
>     >     }
>     >     remote-main {
>     >       auth = pubkey
>     >       id = moon
>     >     }
>     >     remote_addrs = moon
>     >     version = 2
>     >     vips = 0.0.0.0
>     >   }
>     > }
>     >
>     > Routing table 220 is empty on moon. Is that how it's supposed to be? This is its auto-generated swanctl configuration:
>     >
>     > [moon] $ cat /etc/swanctl/swanctl.conf 
>     > connections {
>     >   alice {
>     >     children {
>     >       alice {
>     >         local_ts = 10.0.0.0/24 <http://10.0.0.0/24> <http://10.0.0.0/24>
>     >         updown = /nix/store/jdcviy5z25xamq35g8k9qbdpskkx3w9g-strongswan-5.6.0/libexec/ipsec/_updown iptables
>     >       }
>     >     }
>     >     local-main {
>     >       auth = pubkey
>     >       certs = moonCert.der
>     >       id = moon
>     >     }
>     >     pools = alice
>     >     remote-main {
>     >       auth = pubkey
>     >       id = alice
>     >     }
>     >     version = 2
>     >   }
>     >   carol {
>     >     children {
>     >       carol {
>     >         local_ts = 10.0.0.0/24 <http://10.0.0.0/24> <http://10.0.0.0/24>
>     >         updown = /nix/store/jdcviy5z25xamq35g8k9qbdpskkx3w9g-strongswan-5.6.0/libexec/ipsec/_updown iptables
>     >       }
>     >     }
>     >     local-main {
>     >       auth = pubkey
>     >       certs = moonCert.der
>     >       id = moon
>     >     }
>     >     pools = carol
>     >     remote-main {
>     >       auth = pubkey
>     >       id = carol
>     >     }
>     >     version = 2
>     >   }
>     > }
>     > pools {
>     >   alice {
>     >     addrs = 10.0.0.1
>     >   }
>     >   carol {
>     >     addrs = 10.0.0.2
>     >   }
>     > }
>     >
>     > I'm sure I'm not configuring something correctly. Can somebody point me in the right direction to get this test succeeding?
>     >
>     > Regards,
>     >
>     > Bas
>     >
>     >
>     >
> 
> 
> 

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