Operational Defect Database
BugZero found this defect 2498 days ago.
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WatchGuard Technologies | kA10H000000g3cWSAQ
Emails from Office365 users denied because of SMTP proxy default header size limit
Last update date:
7/17/2017
Affected products:
Firebox M200
Firebox M300
Firebox M270
Firebox M370
Firebox M470
Firebox M570
Firebox M670
Firebox M290
Firebox M390
Firebox M400
Firebox M500
Firebox M440
Affected releases:
All
Fireware
11.x
11.10.x
11.10
11.10.1
11.10.2
11.10.3
11.10.4
11.10.5
11.10.6
11.10.7
Fixed releases:
All
Description:
Issue
If you use the SMTP proxy with default configuration options, emails from users of Office365 will frequently fail to pass because the default header size in the proxy configuration is too low. When this occurs, Traffic Monitor displays a message that looks like this:Deny 1-Trusted 0-External tcp 198.51.100.2 203.0.113.2 39473 25 msg="ProxyDeny: SMTP header size too long" proxy_act="SMTP-Outgoing.1" headers_size="21157" (SMTP-proxy-00)
Workaround/Solution
To avoid this issue, increase the allowed header size in the SMTP proxy. In Policy Manager 1. In Policy Manager, double-click the SMTP proxy policy that handles inbound email.The Edit Policy Properties dialog appears. 2. Adjacent to the proxy action name. click View/Edit Proxy.The SMTP Proxy Action Configuration dialog appears. 3. In the General section, increase the Set the maximum email header size to 30000 bytes. 4. Click OK to close the SMTP Proxy Action Configuration dialog. 5. Click OK to close the Edit Policy Properties dialog. 6. Save the configuration to the Firebox. In Web UI 1. In the Firebox Web UI, select Firewall > Firewall Policies. 2. Select the SMTP proxy policy that handles inbound email and select Action > Edit Policy.The Firewall Policies / Edit policy page appears. 3. Select the Proxy Action tab. 4. In the General section, increase the Set the maximum email header size to 30000 bytes. 5. Click Save.
