> Source: [sk102422](https://support.checkpoint.com/results/sk/sk102422)

# sk102422 - "fw_full" process / "fwd" process on Security Gateway consumes CPU at high level when NAT configured for large network to network translations

| Property | Value |
|----------|-------|
| Solution ID | sk102422 |
| Date Created | 2014-09-09 |
| Last Modified | 2022-11-24 |
| Technical Level | Advanced |
| Products | Security Gateway |
| Versions | R81.20, R81.10 (EOS), R81 (EOS) |
| OS | Gaia |

## Symptoms

- * FireWall logs are not generated/sent by Security Gateway during this issue.
* After configuring NAT for a large networks like Class A network (subnet mask 255.0.0.0; for example, 10.0.0.0/8) or multiple Class B networks, output of '`top`' command shows that "fw_full" process / "fwd" process consumes CPU at very high level - up to 100%  

  *Example for "fw_full" process:*

  ```
  PID  USER     PR    NI   VIRT  RES  SHR S  %CPU  %MEM  TIME+    COMMAND
                                             
  4933 admin    25    0    431m  41m  23m R  92    2.1  35:21.29  fw_full
  ```

* *$FWDIR/log/fwd.elg* file repeatedly shows errors like these (for consecutive IP addresses):  

  ```
  
  fwarp_get_arp_interface: no interface found on same subnet as valid ip address: x.x.x.11
   fwarp_make_arp_entry: can't find arp interface for address: x.x.x.11
  fwarp_get_arp_interface: no interface found on same subnet as valid ip address: x.x.x.12
   fwarp_make_arp_entry: can't find arp interface for address: x.x.x.12
  fwarp_get_arp_interface: no interface found on same subnet as valid ip address: x.x.x.13
   fwarp_make_arp_entry: can't find arp interface for address: x.x.x.13
  ```

* *# fw ctl arp* command shows multiple ARP entries for a single subnet
* VPND daemon might crash during this issue.

## Cause

Erroneous configuration of Automatic Static NAT on a network object causing the gateway to add a huge number of proxy ARP entries.

## Solution

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