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SSG5 PPTP Passthrough - Inbound

  • 1.  SSG5 PPTP Passthrough - Inbound

    Posted 10-29-2014 10:43
      |   view attached

    Ok, so I've searched this forum (and the Internet) extensively for an answer to this problem and I find the same answer every time, that does not solve the problem. 

    Here is the senario:  I have a Windows VPN Servers (PPTP) behind an SSG5.  I have followed the following articles (http://kb.juniper.net/InfoCenter/index?page=content&id=KB5471&smlogin=true, http://www.ezeyme.com/configure-juniper-ssg-5-pass-through-pptp-traffic) to a "T" and I can not get GRE to pass through the SSG5.   My configuration is listed below, any thoughts or ideas would greatly be appreciated.

     

    Total Config size 6447:
    unset key protection enable
    set clock ntp
    set clock timezone -5
    set clock dst recurring start-weekday 2 0 3 02:00 end-weekday 1 0 11 02:00
    set vrouter trust-vr sharable
    set vrouter "untrust-vr"
    exit
    set vrouter "trust-vr"
    unset auto-route-export
    exit
    set service "CustomPPTP" protocol 47 src-port 0-65535 dst-port 2048-2048
    set service "CustomPPTP" + tcp src-port 0-65535 dst-port 1723-1723
    unset alg sip enable
    unset alg mgcp enable
    unset alg sccp enable
    unset alg sunrpc enable
    unset alg msrpc enable
    unset alg sql enable
    unset alg rtsp enable
    set alg pptp enable
    set alg appleichat enable
    unset alg appleichat re-assembly enable
    unset alg h323 enable
    set alg sctp enable
    set auth-server "Local" id 0
    set auth-server "Local" server-name "Local"
    set auth-server "XXXXXX" id 1
    set auth-server "XXXXXX" server-name "x.x.32.131"
    set auth-server "XXXXXX" account-type admin
    set auth-server "XXXXXX" radius secret "/dzJ4w7fNcjcQosGq/CsAfU12hn44abDGA=="
    set auth default auth server "Local"
    set auth radius accounting port 1646
    set admin name "localadmin"
    set admin password "nBOxB7rpHJcJc/vBAs5PltEtbODM6n"
    set admin auth web timeout 10
    set admin auth dial-in timeout 3
    set admin auth server "XXXXXX"
    set admin auth remote primary
    set admin auth remote root
    set admin privilege read-write
    set admin format dos
    set vip multi-port
    set zone "Trust" vrouter "trust-vr"
    set zone "Untrust" vrouter "untrust-vr"
    set zone "DMZ" vrouter "trust-vr"
    set zone "VLAN" vrouter "trust-vr"
    set zone "Untrust-Tun" vrouter "trust-vr"
    set zone "Trust" tcp-rst
    set zone "Untrust" block
    unset zone "Untrust" tcp-rst
    set zone "MGT" block
    unset zone "V1-Trust" tcp-rst
    unset zone "V1-Untrust" tcp-rst
    set zone "DMZ" tcp-rst
    unset zone "V1-DMZ" tcp-rst
    unset zone "VLAN" tcp-rst
    unset zone "Untrust" screen tear-drop
    unset zone "Untrust" screen syn-flood
    unset zone "Untrust" screen ping-death
    unset zone "Untrust" screen ip-filter-src
    unset zone "Untrust" screen land
    set zone "V1-Untrust" screen tear-drop
    set zone "V1-Untrust" screen syn-flood
    set zone "V1-Untrust" screen ping-death
    set zone "V1-Untrust" screen ip-filter-src
    set zone "V1-Untrust" screen land
    set interface ethernet0/1 phy full 100mb
    set interface ethernet0/2 phy full 100mb
    set interface ethernet0/3 phy full 100mb
    set interface ethernet0/4 phy full 100mb
    set interface ethernet0/5 phy full 100mb
    set interface ethernet0/6 phy full 100mb
    set interface "ethernet0/0" zone "Untrust"
    set interface "ethernet0/1" zone "Null"
    set interface "bgroup0" zone "Trust"
    set interface bgroup0 port ethernet0/1
    set interface bgroup0 port ethernet0/2
    set interface bgroup0 port ethernet0/3
    set interface bgroup0 port ethernet0/4
    set interface bgroup0 port ethernet0/5
    set interface bgroup0 port ethernet0/6
    unset interface vlan1 ip
    set interface ethernet0/0 ip x.x.206.194/29
    set interface ethernet0/0 route
    set interface bgroup0 ip x.x.47.1/30
    set interface bgroup0 route
    unset interface vlan1 bypass-others-ipsec
    unset interface vlan1 bypass-non-ip
    set interface ethernet0/0 ip manageable
    set interface bgroup0 ip manageable
    set interface ethernet0/0 manage ping
    unset interface bgroup0 manage telnet
    unset interface bgroup0 manage web
    unset interface vlan1 manage ping
    unset interface vlan1 manage ssh
    unset interface vlan1 manage telnet
    unset interface vlan1 manage snmp
    unset interface vlan1 manage ssl
    unset interface vlan1 manage web
    unset zone V1-Trust manage ping
    unset zone V1-Trust manage ssh
    unset zone V1-Trust manage telnet
    unset zone V1-Trust manage snmp
    unset zone V1-Trust manage ssl
    unset zone V1-Trust manage web
    unset zone V1-DMZ manage ping
    set auth-server "XXXXXX" src-interface "bgroup0"
    set interface ethernet0/0 vip interface-ip 2048 "CustomPPTP" x.x.32.132
    set interface "serial0/0" modem settings "USR" init "AT&F"
    set interface "serial0/0" modem settings "USR" active
    set interface "serial0/0" modem speed 115200
    set interface "serial0/0" modem retry 3
    set interface "serial0/0" modem interval 10
    set interface "serial0/0" modem idle-time 10
    set tftp source-interface bgroup0
    set flow tcp-mss
    set flow path-mtu
    unset flow no-tcp-seq-check
    set flow tcp-syn-check
    unset flow tcp-syn-bit-check
    set flow reverse-route clear-text prefer
    set flow reverse-route tunnel always
    set console page 0
    set domain netops
    set hostname XXXXXX1
    set pki src-interface bgroup0
    set pki authority default scep mode "auto"
    set pki x509 default cert-path partial
    set dns host dns1 x.x.32.131 src-interface bgroup0
    set dns host dns2 8.8.8.8 src-interface ethernet0/0
    set dns host dns3 75.75.75.75 src-interface ethernet0/0
    set dns host schedule 06:28
    set address "Trust" "x.x.32.0" x.x.32.0 255.255.240.0
    set crypto-policy
    exit
    set ike respond-bad-spi 1
    set ike ikev2 ike-sa-soft-lifetime 60
    unset ike ikeid-enumeration
    unset ike dos-protection
    unset ipsec access-session enable
    set ipsec access-session maximum 5000
    set ipsec access-session upper-threshold 0
    set ipsec access-session lower-threshold 0
    set ipsec access-session dead-p2-sa-timeout 0
    unset ipsec access-session log-error
    unset ipsec access-session info-exch-connected
    unset ipsec access-session use-error-log
    set xauth default dns1 x.x.32.131
    set xauth default dns2 8.8.8.8
    set url protocol websense
    exit
    set policy id 1 from "Trust" to "Untrust" "Any" "Any" "ANY" nat src permit
    set policy id 1
    exit
    set policy id 2 from "Untrust" to "Trust" "Any" "VIP(ethernet0/0)" "CustomPPTP" nat src permit log
    set policy id 2
    exit
    set nsmgmt bulkcli reboot-timeout 60
    set ssh version v2
    set ssh enable
    set config lock timeout 5
    unset license-key auto-update
    set telnet client enable
    set ssl encrypt 3des sha-1
    set ntp server "192.5.41.41"
    set ntp server src-interface "ethernet0/0"
    set ntp server backup1 "192.15.41.209"
    set ntp server backup1 src-interface "ethernet0/0"
    set ntp max-adjustment 10
    set snmp port listen 161
    set snmp port trap 162
    set snmpv3 local-engine id "0162122009000484"
    set vrouter "untrust-vr"
    set route 0.0.0.0/0 interface ethernet0/0 gateway x.x.206.198
    exit
    set vrouter "trust-vr"
    unset add-default-route
    set route x.x.32.0/20 interface bgroup0 gateway x.x.47.2
    set route 0.0.0.0/0 vrouter "untrust-vr" preference 20
    exit
    set vrouter "untrust-vr"
    exit
    set vrouter "trust-vr"
    exit

     

    Output from traffic log is attached.

    Attachment(s)

    txt
    getlog.txt   860 B 1 version


  • 2.  RE: SSG5 PPTP Passthrough - Inbound

    Posted 10-29-2014 10:51

    Per your log, it shows that the GRE is timing out.  This indicates that the server isn't responding to the traffic.  Can you run a debug flow basic to see the traffic flow?

     

    http://kb.juniper.net/InfoCenter/index?page=content&id=KB23844#basicdebug



  • 3.  RE: SSG5 PPTP Passthrough - Inbound

    Posted 10-29-2014 11:06
      |   view attached

    Thank you for the quick reply.  The log is attached.

     

     

    Attachment(s)

    txt
    flowlog.txt   9 KB 1 version


  • 4.  RE: SSG5 PPTP Passthrough - Inbound

    Posted 10-29-2014 11:14

    Try removing nat src from policy ID 2.



  • 5.  RE: SSG5 PPTP Passthrough - Inbound

    Posted 10-29-2014 11:32
      |   view attached

    same result, althought it does look like it's routing GRE to the correct location now.  Just to clarify, I took the SSG5 out and configured a SOHO router with port forwarding and the VPN worked fine.  New flow log is attached.

     

     

     

    Attachment(s)

    txt
    flowlog2.txt   9 KB 1 version


  • 6.  RE: SSG5 PPTP Passthrough - Inbound

    Posted 10-29-2014 11:40

    Can now see the bidirectional flows, but the GRE response is never seen by the firewall.  Can you run a pcap on your server to see what it is receiving/sending?



  • 7.  RE: SSG5 PPTP Passthrough - Inbound

    Posted 10-29-2014 11:58
      |   view attached

    Pcap is attached.

     

     

    Attachment(s)

    zip
    PCAP.zip   3 KB 1 version


  • 8.  RE: SSG5 PPTP Passthrough - Inbound

    Posted 10-29-2014 12:07

    The server isn't receiving the GRE requests.  The firewall shows that it is forwarding the packet out e0/0.  Try "unset flow route-cache"



  • 9.  RE: SSG5 PPTP Passthrough - Inbound

    Posted 10-29-2014 12:31
      |   view attached

    Unfortunately that didn't help either.  From the SSG5 I'm able to ping the VPN server so I don't think it's a routing issue. Plus I was able to get port forwarding for RDP working to the server (which I currently have removed from the config). New pcap is attached.

    Attachment(s)

    zip
    PCAP2.zip   2 KB 1 version


  • 10.  RE: SSG5 PPTP Passthrough - Inbound

    Posted 10-30-2014 12:43

    Any other ideas out there?  I've been working on this issue for 3 or 4 days now with zero progress...  



  • 11.  RE: SSG5 PPTP Passthrough - Inbound

    Posted 10-30-2014 13:29

    Still no GRE in the pcaps (filter: GRE).  Can you provide the output for "debug flow basic" again after disabling the route cache?



  • 12.  RE: SSG5 PPTP Passthrough - Inbound

    Posted 10-31-2014 10:10
      |   view attached

    New flow log is attached.

    Attachment(s)

    txt
    flowlog3.txt   13 KB 1 version


  • 13.  RE: SSG5 PPTP Passthrough - Inbound
    Best Answer

    Posted 10-31-2014 10:40

    Try "unset alg pptp enable".  I can see that the ALG is being attached, and the GRE traffic is being routed out e0/0.



  • 14.  RE: SSG5 PPTP Passthrough - Inbound

    Posted 10-31-2014 11:36

    Wow that actually fixed it!  Huh, I never would have guessed that would be the issue.   Thank you very much for figuring this out, this was driving me insane.  I owe you a beer my friend! 



  • 15.  RE: SSG5 PPTP Passthrough - Inbound

    Posted 10-31-2014 11:40

    That ALG is actually disabled by default.



  • 16.  RE: SSG5 PPTP Passthrough - Inbound

    Posted 10-31-2014 11:50

    I do remember enabling that ALG but I don't remeber why... Thanks again for the help!