FTP packets are dropped by Edge Firewall in using NSX-v 6.4.11 or later versions
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FTP packets are dropped by Edge Firewall in using NSX-v 6.4.11 or later versions

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Article ID: 332494

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Updated On:

Products

VMware NSX

Issue/Introduction

When FTP ALG is configured in NSX Edge firewall, FTP data connection cannot be established by dropping packets by Edge firewall as this.

<4>Dec 5 23:35:13 NSX-edge-28-0 firewall[]: [default]: ACCEPT_133173IN= OUT=vNic_0 SRC=10.50.60.70 DST=10.20.30.40 LEN=52 TOS=0x02 PREC=0x00 TTL=127 ID=11893 DF PROTO=TCP SPT=51816 DPT=21 WINDOW=8192 RES=0x00 CWR ECE SYN URGP=0
<4>Dec 5 23:35:13 NSX-edge-28-0 firewall[]: [default]: DROP_131073IN= OUT=vNic_1 SRC=10.20.30.40 DST=10.50.60.70 LEN=52 TOS=0x02 PREC=0x00 TTL=124 ID=26151 DF PROTO=TCP SPT=20 DPT=51817 WINDOW=32768 RES=0x00 CWR ECE SYN URGP=0
<4>Dec 5 23:35:16 NSX-edge-28-0 firewall[]: [default]: DROP_131073IN= OUT=vNic_1 SRC=10.20.30.40 DST=10.50.60.70 LEN=52 TOS=0x02 PREC=0x00 TTL=123 ID=26153 DF PROTO=TCP SPT=20 DPT=51817 WINDOW=32768 RES=0x00 CWR ECE SYN URGP=0
<4>Dec 5 23:35:22 NSX-edge-28-0 firewall[]: [default]: DROP_131073IN= OUT=vNic_1 SRC=10.20.30.40 DST=10.50.60.70 LEN=48 TOS=0x00 PREC=0x00 TTL=123 ID=26154 DF PROTO=TCP SPT=20 DPT=51817 WINDOW=32768 RES=0x00 SYN URGP=0

Resolution

This issue is resolved in VMware NSX Data Center for vSphere 6.4.13.


Workaround:
To workaround the issue, enable "net.netfilter.nf_conntrack_helper" on the NSX Edge:

  1. Connect to the NSX Manager as admin and enter enable mode by typing: en
  2. Enter engineering mode by typing: st en
  3. Enter the NSX Manager root password: IAmOnThePhoneWithTechSupport
  4. Get the password for the Edge by typing: /home/secureall/secureall/sem/WEB-INF/classes/GetSpockEdgePassword.sh
  5. Access the Edge VM console, log in as the admin user and enter enable mode by typing: en
  6. Enable engineering mode by typing: debug engineeringmode enable
  7. Exit enable mode by typing: disable
  8. Enter the root shell on the Edge by typing and using the password from step #4: st en
  9. Run commands as followings:
echo "net.netfilter.nf_conntrack_helper = 1" >> /etc/sysctl.conf
sysctl net.netfilter.nf_conntrack_helper=1