Bug 41073
| Summary: | IP packets have been lost when only 20 POP clients access at same time. | ||||||
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| Product: | [Retired] Red Hat Linux | Reporter: | Keiichi Mori <kmori> | ||||
| Component: | kernel | Assignee: | Arjan van de Ven <arjanv> | ||||
| Status: | CLOSED NOTABUG | QA Contact: | Brock Organ <borgan> | ||||
| Severity: | high | Docs Contact: | |||||
| Priority: | medium | ||||||
| Version: | 7.1 | ||||||
| Target Milestone: | --- | ||||||
| Target Release: | --- | ||||||
| Hardware: | i686 | ||||||
| OS: | Linux | ||||||
| Whiteboard: | |||||||
| Fixed In Version: | Doc Type: | Bug Fix | |||||
| Doc Text: | Story Points: | --- | |||||
| Clone Of: | Environment: | ||||||
| Last Closed: | 2001-05-21 03:06:13 UTC | Type: | --- | ||||
| Regression: | --- | Mount Type: | --- | ||||
| Documentation: | --- | CRM: | |||||
| Verified Versions: | Category: | --- | |||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||
| Embargoed: | |||||||
| Attachments: |
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Dave: Could you take a look ? kmori: are you in a position to test a patch ? I am not in development team, I am in service team. But if you give me a patch, I'll test it. Created attachment 18732 [details]
Proposed patch
Thank you for creating attachment. I could get a patch. I tested this patch, however, kernel had still lost packets. This problem is caused by xinetd specification. Because listen() backlog value defined by xinetd is low, kernel drop client's requests. |
From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux 2.4.2-2 i686; en-US; 0.7) Gecko/20010316 Description of problem: When 20 POP clients using "telnet <server></server> 110" and "expect" access to at same time, xinetd can not fork only 18 process. Because select() function in xinetd main_loop() catch the changed status at 110 port, only 18 times. Packet dump by "ethereal" on POP Server is here:(station100 is a POP Server, station67 is a POP Client) 732 1.830000 station64 station100 TCP 32775 > pop3 [SYN] Seq=3399523946 Ack=0 Win=5840 Len=0 733 1.830000 station100 station64 TCP pop3 > 32775 [SYN, ACK] Seq=3802504036 Ack=3399523947 Win=5792 Len=0 ! 750 1.830000 station64 station100 TCP 32775 > pop3 [ACK] Seq=3399523947 Ack=3802504037 Win=5840 Len=0 * 18084 5.430000 station100 station64 TCP pop3 > 32775 [SYN, ACK] Seq=3802504036 Ack=3399523947 Win=5792 Len=0 * 22351 11.430000 station100 station64 TCP pop3 > 32775 [SYN, ACK] Seq=3802504036 Ack=3399523947 Win=5792 Len=0 Response to [SYN,ACK] reached the Link layer. But It seems not to reached the Transport layer. I think packet have been lost in Network layer. Only 20 clients accessed, why packet have been lost? How reproducible: Always Steps to Reproduce: 1.20 POP clients access to POP server at same time.(very critical) 2. 3. Additional info: